I have trouble coping with the fact that my wif had sexual relations before we met , it is hard not to be bitter about it, what can I do without discouraging my wife about this

Well that is really your problem, not hers, she chose you and is with you that is what should be important.

If you have to go get counseling, in fact she did not even have to tell you, her past is just that her past, should not matter if she was a drug using hooker, if she is not with you and a loving wife that is all that matters.

I wouldn't suggest sharing your bitterness with her as there is absolutely nothing she can do to fix this problem. Marriages are difficult enough without adding additional complications, especially ones that you made the decision to live with when you got married and that have no bearing on your future together. She chose you. Love her without prejudice in your heart.

Yes, I agree with everyone else. When you married her you accepting her past. Don't bring it up and move past it. You married her and she married you, the past is the past.