"Ok, time to come clean- I didn't exactly get this from a rusty nail...."

"I remember when I used to get away with telling The Little Woman that I picked up Hepatitis C by touching someone else's razor, or by picking up the wrong knife.  She was really sympathetic back then, and gave me a speech about 'for better or for worse' or some such bilge.  That was really adorable.  Those were good times."

"Then some bastard invented the internet, and suddenly Clueless Suzy could do her own research about Hepatitis C, and she found out that more than 75% of infections come from intravenous drug use and unprotected sexual intercourse.  Suddenly she felt betrayed by me, and I felt betrayed by The Google. "

"It didn't even help that Hepatitis C now has a cool hip name- HepC.  Come on, who wouldn't want a little HepC?  Hmmm...turns out the answer is 'my wife,' who thought she was safe as long as she didn't touch my razor or any knives I had been handling after suffering a cut.  Ooops, sorry honey."

"And sorry I didn't tell you about what me and my boys did after the big meeting during our business trip to Vegas back in '98.  But once my doctor cleared me for HIV and Syphilis, I thought I was in the clear- um, I mean, I thought WE were in the clear.  Hey, at least I'm not shooting up anymore, that's something, right honey?  Honey?"

Personally?  I'd take action by dumping this guy in exchange for a nice divorce settlement.  You can take that "For Better or For Worse" bit only so far.