No, I wouldn't worry about the heart thing. To be honest, I don't know why a grown woman would write on her hands anyway (or allow anyone else to do it), but that's just me.
Quote: that he wanted me to marry another woman and W another man.
I don't think I'd worry too much about this, either. Your son probably just sees that neither of you are happy right now, and of course he loves you both and he wants you both to be happy, and he probably sees this as a way for both of you to be happy again. It does make me wonder, though, if your W has had some sort of discussion with him. Of course, I'm sure he has friends whose parents are D'd and have Re-M'd.