Eva, I am sorry that you are struggling with this issue and that you relationship has ended. You obviously are doing lots of soul searching.
I am glad that you figured out that your partner's behavior didn't have anything to do with you. His sexual interests in prostitutes preceeded your relationship. I can't explain why this attracts him, but he is not alone. Some men seek the company of prostitutes on a regular basis. But this doesn't make it any more acceptable to their partners, if they have them. Given the possibility of sexually transmitted diseases, the behavior is dangerous. I'm glad you are no longer have sexual relations with him.
As to your mother's advice, I understand that this perspective is much more common in Europe than in the U.S.. I don't know of too many women who think that as long as their husbands love them, they shouldn't worry if there are extramarital affairs. I know that are some women who pretend nothing is going on when there is, but I don't think they would openly condone the behavior.
Having said that, you need to decide what works for you. No two people are alike. I do agree that it is often the case that men think affairs can be "emotionless." Women generally don't understand this perspective because for them, sex and love are usually very much connected. Not always, but usually. Men can separate the two better.
However, this is not to say that women should feel okay about men seeking outside sex. Personally, I think affairs and marriages don't go together very well at all. Fidelity and trust are important building blocks to having a loving relationship.
