Honestly, IMHO it sounds like your husband is cake eating to the highest order. I let my STBX do that for way too long and now she is where she always planned to be - with OM/boss. After she moved out we dated too. Heck, we even went on vacations together! She used all the words they all do: "space" "time" "friends" blah, blah, blah. The reality was that she was simply trying to end our marriage without looking guilty and without it looking like she was aiming for him the whole time.
How many other women does there need to be before you stop? Is there an ounce of commitment to you in him? He will always blame you in some way (they all do) for his actions. But he CHOOSES to act the way he does. Believe nothing of what you hear and half of what you see.
Being as objective as possible, what do you actually see?