Just an update: We started counseling today - 12:00. We mainly filled the counselor in on what has been going on, set some ground rules and talked about what we want to achieve in our sessions. It's all the same stuff we've been talking about at home over and over, but it felt good to talk to someone about it. We go again in 2 weeks. In the mean time, we'll slow down and take things 1 day at a time.
The girl he had his affair with left for bootcamp on the 22nd of May so she's gone for now. Counselor says this is not a bad thing - I just hope it's not delaying the inevitable. Again, 1 day at a time.
Also wanted to say , thanks for all the public and private support / comments. This site is the best one I've found.