I'm really mad, should I revenge?

Sad and Mad

I've been seeing this man for almost two years. I'm deeply in love with him. Although I did not trust him completely I do not have too much doubt about his love for me. Until last week, I found out that he have been seeing someone else besides me. It hurts me really badly and right now I do not know how I'm going to go through life without him. I've decided to leave him despite the yearning I feel for him. Yesterday he called me at night and we talked about it. He told me that he loves both of us, me and her and he wants me to stay with him and also let him stay with her. I've told him that he will have to choose between the two of us and he refused to do so. Worse, he suggested that we all should move in and live together and his fantasy has always been having a "threesome" sexual relationship.

That shocked me. It hurts me and it also anger me beyond belief. I truly we have something really deep together and I've made so many plans for us to be together for the rest of our lives. Now my dreams are shattered. I'm all alone and so depressed.

It's not the first time he've done something like this. Three months into our relationship I found out he has been married. I wanted to leave him then but was not able too since he've promised to leave her. He actually did leave his wife and I thought that we could live happily ever after.

A few months after that while we were getting together with a bunch of friends and drinking, one of my girlfriend got drunk and were sleeping in the bedroom. I was a little drunk too so I lay down besides her. The next thing I know he was laying next to me, caressing her and started to kiss her. I got out of bed crying and running down the stair. He followed and begged for my forgiveness. I was stupid enough again to forgive him....Until now....

I am feeling so low now, like a loser. I have no directions in my life anymore and feel really lost

All I want now is to pay back for all the pain he has caused me. I know things about him that can really hurt him financially. And I really want to hurt him back so he can feel the pain I am feeling now. The advice I need is should I just forget about the whole thing or should I revenge so I can feel better. Please help!