Several years ago right after my divorce from my first wife the ex-wife of a very good friend called and expressed interest in dating some. We talked about it for a bit and I told her that I would get back in a day or two. I called my friend soon after and expressed to him our mutual interest and asked if he felt this would or could potentially be a problem between him and I. He laughed, said go for it and wished me luck.
End of the story goes something along the lines of I know now why he divorced her!! It also gives us a few laughs when we talk over a few beers.