Please advice me what to do?

Where do you live? What's the cultural environment?

You don't need to tie yourself to this jerk forever. Leave him.

As for future marriage, you have a few options.
1) Tell your future husband that you're not a virgin. When in the relationship should you do this? When things are serious and you are talking marriage. If it's important to him, he might just walk. Personally, I find that shallow and stupid on someone's part, but there are people who do that, and there is the culture of thinking a virginal woman is all-important and that may be the case where you live.
2) Have sex with your future husband and thereby avoid the virginity issue at time of marriage. Do you tell him you're not a virgin before the first time you have sex? I don't honestly know; play it by ear.
3) Lie. I don't normally advocate lying in relationships but I find the whole idea of promoting female virginity to the exclusion of women's happiness to be incredibly backward and unrealistic.

You don't have to stay with a man because you had sex with him.

I tell you this, even when I know that your culture tells you that you must stay.

He is not a good man for you. Now you know that.

Just break up with him. You will have other relationships. He's a loser.

The guy is a bum. Trust your instincts. Get rid of him as fast as you can. Your culture may tell you your virginity is important, but believe me, it has nothing to do with it. You are a woman now, an adult and you must trust in yourself and let no one disrespect you.

I was asking about the culture because in some places she could be endangered by initiating a break-up with a guy who doesn't want to break up. I wasn't about to advise her to stick with him, I was just thinking it's best to suggest safe ways to do so.