So, What about Bob?

[NTX_Dad]

My fear is that Bob knows your marriage was rocky and is trying to be flirtatious to see if he can tip it and make it fall over so he can pick up the pieces. During this phase (anytime really), a marriage doesn't need an outside force to confuse things. I suspect that is out EA's start. A little joking, a compliment here and there. I had a weird feeling he's "working it".

Unfortunately you can't control him. And you can't control your wife. You can only control you, so continue your path and continue your redemption, and be the guy that your wife would be a fool to leave.

You can nicely let her know sometime soon that it makes you feel uneasy considering his past. You'll just need to figure out the right time and the right tone to use.