Another stranger chiming in as well. Hopefully things go as well as this type of thing can. Here's to minimal pain (or good drugs) and restful healing.
As you will find out, I have a "slightly" twisted sense of humor so in the spirit of things....here's a bit of mastectomy humor.
I had a great-aunt named Lois who was rather busty. She was diagnosis'd with breast cancer and had a mastectomy on one side. Being the stubborn, independant, doesn't give a d@mn what others think type of person, she never had reconstructive surgery. Instead, she had a falsie but she didn't like it. Said it moved around too much on her and she would wind up with a boob sticking out of her shoulder so she just quit wearing it. I swear, every time I stood and talked to her, I wanted to lean. Knowing Lois though, the added bonus of throwing people off kilter probably tickled her to no end.
Again, I hope all goes as well as possible and your hubs finds a way to process and deal with everything.