Does this man have a defense??

Two men were lovers. Every Friday after work for three years, Man1 would come home, drink some beer, start to belittle Man2, slap, kick and punch Man2, and then apologize on Saturday morning and promise to stop drinking and never to do it again. After the US Supreme Court outlawed the crime of sodomy in Lawrence v. Texas in the summer of 2003, man1 and Man2 planned to move to Machusetts to get legally married. In all of the excitement and anticipation, Man1 started to drink on Wednesday, Thursday and Friday nights, always culminating in slapping, kicking and punching Man2 and always a remorseful apology. Just as they were loading the car for Beantown last Friday night, Man1 said to Man2, “What’s taking you so long, I’m going to give it to you good,” just before Man2 shot Man1. Does Man2 have any defenses?