I do not think you are unreasonable about how you feel! I think he is the one being unreasonable. The very idea of him having women to call him on his cell phone! He knows he has just admitted to having an A with your best friend and yet he takes these calls?
If I were you, I would have to draw some boundries.....like cut out all cell phone calls from women, stop telling me you love me 5 times a day, and give me some space to breathe and time to adjust to the idea you were doing it with my best friend and the two of you lying to me and making me feel like I was the jerk.
Sorry, I am being negative about this, but it burns me up to see the nerve he has to expect you to be all lovie-dovie after dropping that bomb on you just as he gets back home. I bet if the shoe was on the other foot, it would be different!
Perhaps going to a solotion based C together where these things could be mapped out would work better. You certainly have your work cut out for you. But, I for one do not think you are over-reacting. I think everything you are feeling is perfectly normal and you have every right to feel like you do. He should have told you all of this before he came home. I think he was taking advantage. If he had told you this before.....you may not have wanted him to come back to you. He just did not do you right.
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!