If you were already reading his mobile messages then you were already having some doubts about his behavior.

If he had said that he just made a mistake with another girl and it was just fun, that would be bad enough. But if he says he felt love for her, then he's not worth wasting any more time on.

You will surely be able to find someone better than this man. Guys who cheat on their girlfriends aren't the type of people you can marry and trust, because sooner or later he is going to leave you for someone else.