Mama, I second what Cat said. So freaking what if he was "rollerblading" for 2.5 hours and COULD have been f--king three different women in that time. If he was, then he's much more of an a$$hole than you know and you don't want him anyway.
So what if he COULD have been talking to OW. Maybe if he was he was having the "last" convo with her for the 17th time. You don't know, nor should you care.
I have been thinking this idea for a long time and I can't really figure out how to express it but I will try.
To me, when you reach this point of the "reconciliation" I think one of the things we LBS's have to do it take a big "fcuk it all to hell" leap of faith and just trust the sitch. At this point, he left, then came back (if only figuratively) and seems to be working on things. He SAYS the right things and is now seeming to put his money where his mouth is. I think now it's your turn to just take that leap.
If he turns out to be a liar, then he does, but to just go along second guessing all he says and does is not doing either of you any good, and the sad part is there is not likely to be some magic bullet that gives you 100% assurance that all is right in Mama-ville.
I made that choice long ago and shortly thereafter, things started to get better. I don't know if I knew I was making the choice but I did. I chose to risk exposing myself to this person who hurt me so deeply before but you know what, not exposing myself (um, probably poor choice of words) seemed to me more of a risk. Staying in limbo, one foot on the side of "she's still a cheating b!tch" all the time was hindering my efforts. Was there reason to suspect certain things? Sure, maybe, but that was mostly, if not entirely in my head. Once I got out of my head, and into the moment, again, risking sharing that moment with HER, I found out that my real life was much different than the one in my head.
Mama, you may be hurt by this man again but right now, you are using the sword on yourself, what's worse? Put the sword away, you can still use it if you have to, and just start living a different life than the one that is SO wrapped up in what he is or is not doing.
I guess what I am trying to say, similar to what a14 said, is give it a rest. You have poured your heart into trying, now pour it into living, taking the leap of trust that if you simply start living once again, your H will join you eventually.
Keeping a constant eye out for what may be, what is not, and what you expect is slowly dragging you back to that dark place. Go towards the light Mama. Afford yourself the luxury of believing in something again, and that something is YOU.