I was used and I can't get over this sadness

F(25) sorry it's long.

I feel so stupid and the more I think about it the more upset(crying) I get. I'm antisocial,too trusting and been told I'm naive. I don't have friends because I don't connect well with people. I guess it's easy to see now that I was an easy target.

I've never dated,no boyfriend's,no friends,no one ever interested in me. So it was a huge surprise when HE came up to me. He was a coworker(he just started a few days ago) and asked to be friends,so I said sure. He'd be my first real friend. We talked for a few days and I really liked him. I knew he was seeing someone,so when he asked me out I asked about her.

He said he thinks he's single,I told him to make sure. Next day he said he was and asked if we could start somewhere. I told him about me never dating and we need to start out as friends. I guess I gave him all the ammo he needed.

I went full blown honest with him when he asked questions (I'm a terrible lier). I thought I was getting honest answers in return too. I knew the risk of getting hurt if I agreed to date him. I was so close to saying no,I keep to my bubble a lot. I decided to live a little and stop hiding so much.

Well long story short I let him drag me on from June 2019 till September 2019. I made sure my feelings were real and genuine before I took any next steps with him. Turns out he never liked me,he was just using me because he's an compulsive cheater. He has a girlfriend of 3 years who he cheats on constantly. It hurt so bad finding out and she took him back in a second.She apologized to ME! That just made me feel so much worse,because I saw how much he hurt her too.

I see him everyday now acting like nothing happened. Nothing bad happened to him,but I am stuck with this bag of hurt. Sometimes there's this anger too,I want to do something but know I can't.

I know if I act on the anger I'll lose everything. I can't leave because I need this job. I know "don't date coworkers" is a rule but,I didn't think about it at the time. We always kept work and our relationship separate.

I don't want to date ever again. He was my first everything and he knew that. This sadness is killing me. I don't want to leave the house let a lone the bed,but I know no work= no money= no home .