If his marriage fails, a married man could fall in love with someone else, and that person could be you
Your love life doesn’t need to include the complications of being with a man who is taken. You need to choose as to whether to be with him. It could start as a secret crush and then turn into an affair. The next moment the guy is in love with you. The short answer is, yes, a married man has the capability to fall in love with someone else.
This could be a scenario where his current relationship isn’t working out, and spending time with another person helps him forget what’s going on at home
That said, it’s essential to be careful about this situation. This isn’t only an issue as it relates to marriage. Even if he is dating someone, this could be a big warning sign to stay away. Regardless, cheating is showing disregard for another person’s feelings, and there’s no guarantee that he won’t do it to another person in the future, including you.
A man can love two women at the same time. If a married man is falling in love with another woman, he may need some relationship advice. He doesn’t know whether to stay with his wife or move on. He’s not sure whether or not to act on his feelings. That makes his love life complicated and possibly exciting. However, it’s not fair to the two women involved in this scenario. These individuals deserve to have a man who is dedicated to them.
Someone involved with two women in a monogamous marriage could be engaging in other hurtful behaviors. He might lie to your face saying that he will never leave your side and that he’s going to leave his wife, or he could be seeing yet another person. Remember that he is going behind 
his wife’s back. He didn’t forget his status as a married man, and this is a red flag. That’s why, if you encounter this man or a man that engages in these behaviors, it might not be a good idea to build a romantic relationship with him, which could lead to disappointment and heartbreak.