I read your profile and I understand your feelings. My WH did the same but for some reason didn't leave. When I found out the truth about his plans to leave and there was an OW even though he said there wasn't I was devastated. I could not believe out of the blue he wanted to leave me even though I was trying to talk to him about our problems. I know it is hard to rebuilt trust after such a betrayal and I understand questioning why you feel the way you do even though WS is doing all the right things.
I have discussed this same emotion in MC and our MC has said maybe the A and finding out the truth is really a deal breaker. I will be honest at times I believe it is for me. I have tried to convey my feelings of the A and knowing I tried addressing our problems and he choose to run away and found others who stroked his ego and told him he was right.
The reality is to choose to R you have to eventually let go of the feelings and learn to trust again. My MC says it is a risk only you can make.
IMHO - you have a newborn and you should give yourself a break about all of the A emotions. You can't juggle all these emotions and take care of a newborn.
I sincerely wish you the best.Me BW - 46
Him WH - 53
Together 23 yrs, Married 18
DDay August 2011
2 kids - 13 and 15
Gotta love the life that we livin'