Should I Tell her ?

I've been friends with a guy for a while now, about 5-6 years. He has a girlfriend, I've known that, they've been together for almost 3 years. We've hooked up about 4 times throughout him having a girlfriend. At this point, I'm tired of this situation. Yes I love him, but I'm just tired of all of this. I'm debating whether to tell her what has been going on or not.

Yes I know what I did was wrong, you guys dont have to attack me for it. I'm aware of my mistakes.