I personally wouldn't bring that kind of dynamic to the house, especially if it might make your H uncomfortable and your friend would "not control his mouth."
The way I look at it is this: I would never bring a situation into my home that would cause any embarrassment, hurt feelings, negativity, or situations that could be harmful to my relationship.
Case in point -- I have a good friend who I went to both HS and College with that I dated on and off (nothing serious) but there was always chemistry there. Once things became serious with my H, I didn't put myself in a situation that could be misconstrued in anyway. Good friend came over a few times before my wedding -- to go running with me while I was out of work and H was at work. I always met him on the front porch -- never had him inside. When he came back from the Army, I met him in a public place and had drinks. At no point in time did my H ever had a problem with this (and he knew this history between us), but I avoided situations like the plague.
Me personally, I wouldn't have B over, because a)B has mentioned he can control his mouth and honestly, no one needs to be getting into the middle of your sitch, b)having him come over after H leaves looks like (imo) that you're hiding something from him. C) if B has had a thing for you before, who is to say he won't try and take advantage of the situation and D) it's just a bad idea.
Could ya'll not meet in a coffee shop or public place to avoid a sticky situation? That's just me.
M:32,H 32 T:10, M5 BD/H Move Out: 9/2014 - extreme anger H Mental Illness Diagnosis: 4/15 Served D Papers: 10/15 Divorced: 11/15