
Zencalm, and welcome to the family! It sounds like you are going through a really tough time, and I feel for you while you navigate these difficult waters.
The fact that your fiance has been diagnosed and is in treatment is very important to a healthy outcome, and greatly improves your chances of success.
Generally this phase of your relationship is a tricky one, even if none of the partners have a mental illness it is the time one begins to set boundaries. The first romance is over, and part of deepening love is getting to know each other better and figuring out how to get along. It is often said that it is somewhere around now that the things you used to adore while courting are starting to drive you crazy

So what I am saying is that the utmost caution is needed and it is wise of you approach this board for support.
I am sorry to say this but sleep deprivation is most definitely one of the listed forms of abuse, and I would set a firm boundary around that. There is an inventory here which is most helpful in allowing you to take a good look at your relationship and improve your understanding of what is going on:
https://www.mosaicmethod.com/With the verbal abuse to my mind there is a distinction between what they say when dysregulated and what is said in a calm frame of mind. Picture dysregulation like an electrical storm going through
the brain, kind of like an emotional epilepsy, and that will help you to discount much of what is said. I try and practice deep listening while subtracting my ego from it, sometimes there is important information coming out that helps me to navigate the relationship better. For instance, the uproar about the gifts might be a inverted way to ask the hidden question:"how much do you love me?"" If you hear it in this way, it might be easier for you to relate to. People with BPD, more than most, have everything to lose by trusting the wrong person in love, we can recover from blows that would imperil their very survival. So it will always be a source of huge anxiety. You can do much to reduce conflict and discuss these questions in a healthy way. The best place for you to start is with the Relationship Tools list you will see at the bottom of your screen. The more you practice them the better things will be.
While I perfectly understand your doubts and hesitation about marriage (it is indeed a big decision to take on) I would hesitate about saying it too loudly. Fear of abandonment is at the very core of BPD and you cannot expect calm in your relationship while you stoke these. Are you in counselling? That would be the appropriate place both to get support and think through these issues.
I am a strong advocate of couple counselling before marriage, and many faith-based organizations and non-profits offer this service. Improving communication around expectations and responsibilities would help save many relationships whether or not BPD is in the picture. Prevention is better than cure, any time.
Please keep posting! The more we understand about your situation, the better we can help.

Khib