He sounds just like my ExH. I really doubt this was just 2 kisses. (Sorry).
Look, your H kissed her before and felt NO REMORSE, otherwise he would never have placed himself in this position again. He has left the pub to walk her home, knowing all along how that ended last time. So that's premeditated.
And do you believe that a passionate kiss at the front door, in the dark, knowing a bedroom lay inside....didn't lead to more? No fucking way. I'm sorry, but I just don't buy it. And who the fuck needs "closure" after 2 kisses (is she a teenager??).
And why has she got his mobile number?
Defo get the itemised phone bill - that will tell you loads.
And yes, I'd defo send a text this morning....."sorry, only just saw your texts, bit hungover and slept in...what do you mean?"
My ExH did this and by the time I found out, he'd tried it on with over 10 women. I stayed for 4 years and tried to get past it for the kids, but every time he got pissed he did it again. I left when the kids were 9 and 11, I just couldn't take it anymore. My point here, is that I think once you've crossed that line and been forgiven, it doesn't stop.
The huge hurdle here is that he is going to keep seeing her on a daily basis at work - I couldn't cope with that.
I'm so sorry, what a Pig. Sending big hugs to you. 