As far as I am aware my ex-girlfriend has not been formally diagnosed as having a BPD. When I was with her, the only initial clue of potential issues was when we started dating and someone did say to me once, 'be careful', but would not elaborate further.
When some of her behaviours started I just took these at face value i.e. that it was purely a reflection that I had in fact found my soul mate and could not believe my luck. I had no frame of reference or awareness of BPD at this stage. It's only when the relationship ended and the pain ensued that I went searching for possible answers as I was left completely confounded. I accessed internet 'breakup advice', but it still left many questions unanswered. I came across BPD by chance and it was only then that I noted some similar patterns.
I have reflected on all the behaviours I noticed during our relationship and would like to share these for anyone's thoughts in case I have missed anything else which could account for the behaviours I witnessed and experienced. If nothing else I want to learn from my painful experience. Behaviours as follows:
1) Intense affection from the get go i.e. She said, ‘How I was her soul mate’, ‘sent by the angels to her’, declaring ‘deep love’ frequently and needed constant reassurance i.e. asked whether ‘we had bonded’ and wanted to get engaged by the eighth date and even told her two children to this effect. Very alluring and feminine. Said to me, 'that I had ignited a switch inside her'.
2) After extreme affection from Apr–Nov 2017, then followed by extreme negativity, how I did not care, how I pushed her away from the start, how I was too confident, how I upset her with my comments, how I did not like her children. Ended relationship suddenly with no immediate explanation and said, "We don't want your Xmas presents either." I think the 'we' was in reference to her and her children. Resumed communication, then because I asked for some space due to her frequent negative texts about me, she then said, ‘I would never hear from her again and she was now blocking me everywhere’. This was Feb 2018. Never heard from her since and ignored any contact I made via letter.
3) Contradictions. Said she wanted to get engaged at date eight, but then when suggested getting engaged after eight months, she said she would only get engaged if everything was right, so presumably she felt everything was right after eight dates!
4) Very negative about her ex-husband and how he does not support her with his/her two children. She would frequently be negative about him in front of their children and in front of me. I would often advise her to temper her notes to him so as not to alienate him unnecessarily. He left when the children were very young and remarried and has two children with his current wife (lives close by).

5) Married twice and seemed to have difficult relationship endings. Called or threatened the police on her ex partner, neighbours and contacted the police about me because I sent her some letters when she blocked me everywhere (letters were friendly and none threatening and tried to address the fact that she perceived I did not care about her).
6) Poor relationship with parents. Difficult relationship with her mother and father. Alleges her mother constantly criticises her parenting skills (allegedly says she does not do enough for her children!) and they engaged in periods of ignoring one another for long periods and her father struggles with both her and his wife’s ‘overbearing’ parenting approach. Both tend to do every practical task possible for the children (peel their fruit, clean their rooms and undertake every household task). Her mother and father also have a difficult relationship with each other and were on the verge of splitting.
7) Has two children (boy and girl). The boy has challenging behaviour and both seem very immature for their ages. Tends to do everything for them then complains how lazy they are.

8) Always seems to loom from one crisis to the next and has a chaotic home life with few barriers in-situ. Acts immature and as a peer alongside her daughter. Engages in much teen speak and always on Snapchat, FB, Whatsapp, Twitter etc (she is in her mid 40’s). Would air her difficulties at work and seek support/sympathy.
9) Forever complaining about ailments i.e. sore legs, headaches, period pains and even criticised me for ‘not saying sorry that her ovaries were hurting’. Daughter also has a lot of ailments and health issues. This impacts on activities. Frequent trips to casualty and lots of conversation about health issues and medication.
10) Complained that I did not take enough interest in her children, but then appeared frosty when I suggested undertaking cycling or activities with her son that did not involve her. Very protective of her children to outsiders. Asked her to let me know how her daughter was after she called the GP, but told, 'she would let her father know', but not me. To be fair this was the day when she broke up with me.
11) Very focused on her appearance and did not appear to have any hobbies/interests. Talked about enhancement surgery.
12) Liked to appear to be a victim of circumstances and referred to how she did not like boys/men.
13) Has a babyish type voice and appears to need rescuing from problems. Often complaining about how men have let her down and how her children are demanding and lazy. If offer advice/solutions pertaining to her problems, or children, then not taken well as then this is perceived as criticising her parenting skills.

14) Appears to get very upset about minor issues and holds onto comments and then later draws upon these as a sign of lack of caring.

15) Sudden temper outbursts (no violence noted though).

16) Intense texting all hours and into the early hours. Delay of responses causes her agitation and interpreted as not caring/lack of interest. Very affectionate texting in the initial period, but negative texting during post breakup phase. One day when she annoyed me I was curt with her and then was working in the garage. She phoned me incessantly until I answered.
17) Became jealous. We met at work and she started to question why I was supervising female staff so long and was upset if I did not acknowledge her at work. She did not seem to understand the need to maintain professional boundaries. Asked me if I ever met any single women at the gym or when cycling.
18) Showed no interest in my interests or background career. Did not like me to have independent interests. This was criticised as 'gets on her nerves'.

19) Critical of my friends even those who she had never even met.
20) Did not like me mentioning exe’s and criticised me for talking about them too much, even though she asked the questions. Could not understand why I maintained a friendly relationship with them. I was with my previous ex partner for 19-years and supported her son from the age of 11-30 years old and still maintain a relationship to this day. She did not like this.

21) Destroyed all material related to her own exe’s and did not have any photo’s of her ex-husband (children’s father) on show.

22) Unable to apologise and take responsibility for events. Does not appear to be able to make the connection between cause and effect. When I said, we both had made mistakes with the relationship, she responded with, “I have not made any mistakes!”
23) Very black and white thinking. Does not forgive easily and once an ex always an ex in her view and needs to be cut away. Had very strong views on law and order/capital punishment and was very keen to join a local anti-paedophile group.
24) Had a lot of male friends on Facebook and did not want me to link as friends and also blocked me on Facebook from even accessing her homepage.
25) I never met any of her friends or family.
26) After seven months said the relationship was over simply because I asked her to unblock me on Facebook. Later cited that it was because I pushed her away and how she thought I did not even like her.
27) Very sensitive to criticism, but happily insulting to me. Said food I made was 'gross' and 'minging'. Yet became very upset because I said she looked tired in one photo she sent.
28) Very sexual and willing to engage in unsafe sex. Was not averse to having another child with me initially.
29) After initially breaking up with me continued to text and still needed validation even though she ended the relationship i.e. asking if I thought she was very special and whether I missed her. The next minute hardly any responses and very negative texts about me. Ignored the prospect of ever meeting up and refused to take phone calls from me. Just said 'she needed to think about things'.

30) After saying I would never hear from her again and she was blocking me, did not appear to have any emotional attachment to me whatsoever, or appear perturbed by breaking up. Moved on instantaneously.
31) Although we no longer work in the same place together (I left), when I recently tried to contact an ex-colleague I worked closely with, my ex-colleague ignored my contact attempts. I suspect my character may have been besmirched by my ex. It's a small organisation/team. I cannot prove this of course, but it seems coincidental when I was told to keep in touch with my ex-colleagues.
a lot of BPD red flags there. Did she have any alcohol or substance misuse. threats of suicide or emotional blackmail/attention seeking behaviour? I only marked stuff based mostly on my own experience and what ive read on the subject but it does sound a lot of contributing traits.