I'll try and make an extremely long story short. Just need advice in any way I can get it. Throwaway as my BF uses Reddit 

My boyfriend and I have been together for going on 2 years and he is amazing and can honestly say he handles my BPD very well. He gets sad and angry about it but always tries to help in any way and always forgives me when I get upset and irrational. I wish I could find a flaw or something to indicate why I'm not feeling right about us but I really can't.

Don't know if this is something common with BPD or if it's just me?? I feel like I crave attention outside my relationship and am slipping away from him.. I always come back but then I start to feel bored/unhappy again. Often I feel like I hate being responsible for someone else/their happiness - like it's all too much. And it's better to have a little flirtationship with someone, as there are no expectations for me to make them happy? 

We have had our fair share of issues - his ex being a big one. She is still involved in our lives which I thought I had come to terms with but she does bother me and her presence in our lives is something that seems to annoy me or niggle at me everyday. 

Other than that, there are no real issues. He's supposed to be buying a house and I'm supposed to be moving in. I've tried to explain these feelings to him and leave him - as I feel I'm not being fair to him. But I can't seem to do it, we both always end up upset and neither one of us leaves..

I don't know what I'm looking to gain from this, am I unhappy or just borderline?? Is this a BPD issue or a me issue???