I'm not as good at it as Puppy Dog Tails is, but the obvious lack of respect that he has for you, the level of selfishness and privilege it took for him to make that kind of proposal, and his attempts to make it "all your fault" screams Other Woman to me.
What is the likelihood of this?
Don't go snooping unless a) you're sure you can handle finding out the truth, and b) you're not likely to get caught.
Me: 44, Wife: 39 M: 17 years T: 20 years Bomb on 08/25/09 1/13/10: MC started 1/28/10, 2/8/10: More bombs 8/28/10: Wife moved out No talk of D, no movement