You did the completely right decision. Clearly, this man is a horrible person who has no morals or respect for you. If he cheats on you, right then you know that he is not taking the relationship seriously and does not have any respect for you. Honestly, personally, if I found out he was cheating, I would right away break up with him and confront him. You deserve so much better, It must be so difficult and painful it is to go through a situation like this, but you clearly deserve better than this and that man is no good for you!