Trouble letting go

I'm 23 and I quit my job 6 months ago.. I hated my work place. I made a terrible mistake of dating my team leader and I was stuck. We met at a party, after a night of heavy drinking we just happened to kiss. I wanted to let it go and never talk about it again. Although I did like him even before that happened. I knew that it would just be trouble if I did anything about it. After that party I was told that he was getting out of a bad relationship. He kept trying to talk to me after that happened and I ignored him for a while but eventually gave in. We decided that it wasn't gonna be anything serious. And normally I'm comfortable with keeping things light. We kept our "relationship" from most people at work because that was necessary. That went on for a year. Most people eventually found out and it really didn't look good. He smokes weed everyday and drinks too much. So he's never reliable. I realized I was falling for him so I would end it with him but eventually I would get back again. It reached a point where he wouldn't even take me seriously anymore. Because even if I did end it I had to see him everyday and work with him. I couldn't take it anymore and I wanted to quit. I told him that we are done for good the day I quit. I didn't tell him that he was the reason I quit.

Well, long story short. Its been 6 months since I quit and I'm still with him. He has slept with many women behind my back. But we weren't always together so I can't really say anything. He said he'd stop but who knows. But the past month we have been getting closer. He stoped smoking up or drinking as much as he used to. He's around more. He makes an effort. He has always been a well wisher. He councils me on the job front and to some extent takes care of me(I can be childish at times) as he's 4 years older than I am. But after everything that's happened I can't open up to him. I wouldn't know where to begin. I'm so mad at him for sleeping around and being a stoner but I can't let it out. I do see a bit of change in him but I still don't fight with him or let things out. I just bottle up my feelings. I know the best thing to do is to be done but I can't let go. If I end it he puts in a lot of effort to get me back and the cycle continues. We kind of need each other around to keep us from falling apart.

We have nothing in common. Being from India even our language of comfort is different. He tries to express himself in English when he's far more comfortable speaking Hindi. I do understand Hindi but can't speak the language. I'm from the south and he's from the north. Our cultures are different, languages are different, religions are different, the type of friends we have are different and we try hard to find common ground. But all this scares us away from each other because we didn't want us to become this dependant on each other. And yes, the sexual attraction to each other is amazing. But we definitely don't see a future together. I made mistake starting this in the first place. I just need some peace of mind.

This has been eating me up. I'm becoming lost in life. I finally found myself a job. More than anything I'm hoping it would be a distraction. My self esteem is so low now. I have no hope in life. I feel stupid being in this place when everyone around me is settling down. And I'm not a stupid person. I was smart, confident and lively. The kind of person other girls around me looked up to. Now I'm lost and I feel useless. I'm cutting myself off from the world. I think I'm going into depression. I need help but I'm not confident enough to go seek psychiatrist help face to face.