I always thought, why men cheat. Why does a man fall in love with other women, even if he currently is in a relationship? Why??

The 3 most common reasons why a man fall in love with other women, even if he currently is in a relationship are:
Loneliness: Men often get into relationships when they have been lonely and single for some while. A man feel grateful to a woman for being with him and reward her with relationship.
Compactibility/Suitability: If a man meets less compatible or less suitable woman, he does not notice them and has no dilemma. But when the same man meets more compatible and more suitable woman, he falls in love, because they have more in common with the new woman.
Curiousity for new things: It’s by nature for human, in general, to wanting to know about the new things even though the old which he possessed has better quality than that new which he pursue. An instance was a story of a man who was allowed to open nine out of ten cups, the higher he gets to the tenth cup the better the quality of what is in those cups. After the ninth cup, he was asked NOT to open the tenth cup as what’s in the tenth cup was even miserable than that which is in the first cup. But he refused conformity. Due to curiousity, he opened the tenth cup, and found a snake 🐍 He spook away! 😆 So, applicae to men with women. Men create a dilemma because they want the new women, and at some level recognise that she is a better match, which is why they fell in love. However, they feel loyalty towards the initial woman, who is not so good a match, because she let him near her when no one else would.