First of all, it is necessary to find out whether the boyfriend has completely confessed and correct this problem. If he has completely confessed and corrected the problem, then you can consider forgiving him. However, if he still hides or is not completely frank, then you need to consider this issue more carefully.
Secondly, we need to consider the seriousness of this problem. If this behavior involves sexual behavior or sex trade, it may involve moral and legal issues and need to be considered more seriously. However, if this behavior is simply called a mistake, it may be just a moral problem and can be forgiven.
Finally, you need to consider your emotional and psychological state. If you feel very painful and unacceptable about this behavior, then you need to consider breaking up or seeking psychological counseling. However, if you think it is acceptable, or have gradually adapted to this behavior, then you can consider forgiving him.
In a word, this is a very complicated problem that needs serious consideration. Before making a decision, you need to know the nature and severity of the problem, and take into account your emotional and psychological state.