My advice is not to take that next step because there’s nothing in it for you if you want a committed, monogamous relationship that will lead to marriage. 😕 You can tell him that if he gets divorced, you’d be more than happy to date him, but right now, you don’t want to be the woman on the side.
In addition, remember that a man’s behavior will show you a lot about his character, and he is lying to his wife. The person on the other end of those lies will one day be you, too — if you’re not already. You may justify your entertaining this relationship because YOU think he has a bad relationship with his wife, but only he and she know what happens in their marriage. He’s going to tell you what he thinks you want to hear in order to get you to sleep with him.
Sometimes old family friends fly under the radar because you think you know them based on a past history. Imagine if you just met this guy yesterday, and he started to pursue you, but was married. I bet you’d walk away quickly.
Give yourself what you deserve — a potential Mr. Right who is AVAILABLE to be that man for you! 😉
I hope that helps.