Is loving someone after marriage a mistake?

My partner is already married with a child but unhappy in his marriage. We have connected deeply and become attached; I truly love him. We both feel that we could be happy together. I am willing to care for his child as my own, even if it means not having children of my own. I can't imagine life without him. Prior to meeting him, I experienced a difficult breakup from a 9-year relationship. Rebuilding trust and love was challenging, but somehow I managed to trust and respect him. I don't feel connected to anyone else in the same way. I am attached to him in all ways, and I can't pass a single day without thinking of him. He is conflicted about whether it's right to divorce his wife or leave me. He feels that loving me after marriage might be wrong, so he wonders if we should sacrifice our happiness or if he should pursue a divorce and take the necessary steps. **He is worried about the problems she might face if he initiates a divorce, even though he is unhappy with the marriage and the negative events that have occurred. On the other hand, if they stay together, I might face problems.** Additionally, I am unmarried, so my parents may not agree to a second marriage. However, I am prepared to confront this issue. **If they are happy, I am willing to sacrifice, but I am unsure if I can handle and lead life alone without him, and I cannot envision a life with anyone else.** What should we do? Is loving someone after marriage a mistake? Is getting a divorce a mistake? Should we stay together or make sacrifices and just survive? I'm not even sure if I can survive without him