What to do about an "annoying" friendship?

So, I have a best friend who is three years younger than I am. She vents to me about her boyfriend (now ex), CONSTANTLY. At first, it was okay. We're besties right? We were also room mates. About twice a week, there would be an hour long convo about how she isn't happy or wants to leave him, or what should she cuz he did blah blah. Anyways - it's been almost two years of her complaining, and she has finally broke up with him. This is the third time she has. She always lies to me and says "we aren't talking" yet she still does and ends up with him again, despite my advice and disappointment. She now has just found out he cheated on her, and wants my support, so I tried but I'm losing the energy. I'm just so exhausted with this. In my opinion - it's just stupid. I don't deal with stupid. Stupid situations and people piss me off. I've told her that I really don't want to talk about him anymore, because it's just annoying. I don't want to help anymore. Nothing ever changes. I didn't say it like that obviously, but she still called me a bad friend for not wanting to hear her vent about him and how I "need to be there's for her. Does she not realize how long this has been going on and how annoying it is? Am I seriously a bad friend for wanting to be left alone about this topic? Am I wrong?