Even if you want to compete with his wife, you are not qualified. Personally, I hate people who destroy other people's families. Such a woman really shouldn't live in this world. I suggest you don't become such a person, slowly change your inner thoughts, turn your love into admiration, and slowly fade away. Maybe after your eyes leave him, you will see someone who really suits you.
At that time, it was the best of both worlds, and that kind of love could be blessed by others. If you really can't forget him and think he is necessary, I also hope you don't interfere in his family. It's your business to love other people's homes, and it's your fault to interfere with them. No one will stop you from loving a man, and it's not your fault that you like a married man, as long as you don't destroy other people's families.
If it's their own fault that caused their divorce, it's none of your business. Then you can wait until the end to pursue him. I believe many people will bless you, but personally, this may not happen. It's your own business anyway. Follow your heart, don't go astray, don't cheat, let time dilute and wait. This decision depends on how you weigh it.