Hi Rainy.
My experience with my ex friend (see my "Is this PPD" thread) is similar, but without the making up again afterwards and acting as though nothing happened. He, too, would become clingy with me and it seemed as though he didn't want to listen to his problems. He always had a million problems of his own- at work, with his wife, with people "not understanding him", and even accusing me of being a bad and unsupportive, uncaring friend.

Even though it was one of the most painful moments of my life to lose him as a friend (he was my best online friend for about 7 years: there for me when people IRL weren't), but it ended up being a great thing for my mental health in the end. I've had similar experiences with other people, mostly online, who used me as a sounding board for their own problems while being hurtful to me. In the end, for me, it was not worth it.

So, in the end, (even though he was the one to cut all contact with me in a vicious way), our breakup was a good thing for my own sanity. I know longer had to worry about if I was saying the right thing to him, or if he truly cared about me, or if I was just being used by him, etc.

But, your friendship could be different. I can't say for certain. But I do know in my own case that it turned out for the best when I cut off ties with people who were unreciprocating in terms of support.