This kind of thing really sucks, and its crappy you're going through it. Its wrong to see there as a "wrong" party though; some people have more difficulty with relational attachments than others and can't "deal with" the ambiguity of friendship with complications. Some can.

It often relates to early relationships, especially with family (and I'm not saying it does in this case, just that its common.)

Having a friendship with someone that's ambiguous for you is a challenging thing, it feels like. It would be nice if you could, but...

We all can only deal with that which we're personally equipped for AND we can! develop new strengths.

May I ask, if its not too personal, do you have a therapist?