Based on what you've said, it does sound like your friend has some issues too. That doesn't sound like "normal" behavior. And if that is the case, then I think it's important you try accept that to some degree and adjust your expectations. The same way you would hope your friends would for you, knowing that you're going through a hard time. But it all needs to be balanced, you don't want people to take advantage of you. I think it's important to try and establish what is/isn't acceptable behavior, otherwise you're going to attract the wrong kinds of people into your life. And I sense you're the type of person who would end up blaming yourself for each of these failed relationships, which will make you feel even worse.

What's your plan of action to try and work on some of these issues? Have you discussed this with your therapist?