I strongly suggest you ask them first. Not because of your wishes, but THEIRS. It is a different ball game, and while you think he may be welcome, don't just assume he is and invite him over...after all, he isn't your husband anymore. And don't make the mistake that I did and ask them to accept him, either.
Better man? Not a bad song. I think we all wish that we had married someone better...maybe not someone different, but that our pieces of sh*t would honor their vows.
There are moments in this life when you are so confident in the rightness of your actions, that not even for a second do you consider the option that you might be wrong.