Questions I'd be asking -
Am I normally a suspicious person, or is this unusual (for me to be so doubtful)?
Is it normal for him to meet with colleagues overnight (who you haven't heard of) for 'networking' purposes? Is this part of his normal pattern or unusual?
If he is so 'meticulous', why the change in story re who booked the ticket.
Would a secretary have access to his personal credit card? Has this happened previously?
He may well be completely innocent, I have to confess, that I am in a very suspicious place right now as my H and I have just split up due to him cheating. BUT, a few things don't ring true here.
Firstly, the argument of 'if he was having an affair, surely he would cover it up better', simply doesn't hold water. If you've followed any of the affair threads on here you will see that men are rubbish at covering their tracks. I found out about my Hs affair because he'd left an email in his 'sent' box that he'd sent to her with train booking details for her to come and visit him.
The bit about him saying 'I'll cancel IF YOU WANT ME TOO'. My H used VERY similar lines on me after the first discovery, but whilst still lying about stuff. It was classic emotional twisting of stuff, 'well, if you don't trust me, I'll have to make a big sacrifice' type stuff.
The bit about the 'early night'. I have emails from when H was with the OW, 'oh I'll say night now as having an early night' type stuff was common.
I was never a suspicious person, but a few months before discovering the affair found myself strangely drawn to the relationships forum, specifically the affair threads. Once I discovered the affair I suddenly 'clicked' with loads of other behaviour (mobile on silent, computer on 'private browse', H staying up till 3am often, H frequently switching screens on his computer if I walked in the room). Is your H doing any of these things?
Sorry, I am probably just a bitter old hag who is seeing everything through 'affair' glasses, but something made me feel compelled to post on this one.
Hope you are ok ((())).