It is hard to not have those nagging thoughts, checking texts, etc. Personally I find going down the rabbit hole on this forum and reading others' experiences to be a really good "diversion" (okay, it's not technically a diversion because it ends up being more time I'm sitting thinking about this). It just absorbs some energy, reminds me I'm not alone, etc.
By the way, the fact that you say it was doomed from the beginning/never really going to work : sometimes I think BPD folks end up in relationships that are logistically or otherwise "doomed". There's something about both parties knowing it's not "permanent" on some level that I feel allows certain behaviors and patterns to be enabled or tolerated because "it's not like we're getting married anyway." Anyone agree?
I'll be point blank honest, I never expected mine to work out in the long run. I had hoped that it would, yes. But, in the deep recesses of my mind I knew that it wouldn't. That didn't make my love for her any less, I just sort of looked at it from a standpoint of that I had a loved one with a terminal illness. I planned to spend as much time with her as possible until the day came she left my life. Then, I would grieve her loss and move forward. I know that sounds like a douche thing, but I knew she would sabotage it at some point (or say that I did, even when her behavior led to it) and that's exactly what's happened.
Plus, also in the interest in candidness, we started our relationship up when we were both still married to other people. Don't get me wrong, mine was on its edge and once I got separated and started the proceedings, I thought it would get better between my pwBPD and myself. It didn't. She kept claiming to be getting a divorce but when I would press about details she would get furious with me. As recent as today (we still have contact, even though we've said our goodbyes, detaching is a process) she made the comment about her supposedly-soon-to-be-ex husband (who's she's been divorcing over a year now, according to her even though they have no kids, etc). Having a moment of clarity from my infatuation with her made me realize how many red flags theres been in the past several months, though we've been "talking" to each other almost that entire year.
But, back on topic, we both needed someone at the time it all started again and it simply progressed from there. There were times I thought it would work out, turns out it didn't. Some might say that it was just a relationship that didn't work out, but that's not true. I may catalogue how the past month has made everything fall apart, just to get it off my chest, but the end result is that our "relationship" is coming to a close. I'm tired of the abuse and the lies. Did I
always think it was doomed from the beginning? No. I had hoped it would work, this time. (Un)Fortunately, there won't be a third time.