Hello OP.
Right, sorry to go against the general consensus here, but could he actually be telling the truth about staying in the hotel?
I'm curious about this, as he has acted calmly, has said he wants to give you space, he understands why you're not happy about the messages on his tablet. On other threads where the partners have got angry or shouted or or or, posters on here say they must be angry because they've been caught out. Your OH hasn't behaved in this way.
Also their replies to your questions are about what happened a long time ago. I don't remember the detail of everything that happened a long time ago, but I might remember some of the facts.
I think You said he deletes messages, so could it be that there were others where he asked about the phone, she said I picked it up, it should be in my bag, I'll check? And then she can't find it, so she has to look again and then finds it under the sofa where the contents of her bag had spilled out. I'm always losing things under sofas as things are always falling out of my bag.
I'm just worrying that you're so troubled by this and it can't be good for your health or sanity. Could it be that he really does feel bad for the messages between them that he did stay at the hotel?
I'm probably way off the mark here, but I've been following this thread and my underlying feeling has been that maybe he did stay at the hotel. you went through a tricky patch and have worked through this together and are now in a happy place.
I'm playing devils advocate here because you sound so torn. For what it's worth, I wouldn't be able to forgive the nature of the flirty messages between them, but you seem to be saying that that in itself doesn't worry you as they are good friends, but the lying about where he stayed does.
I'm sorry if I've misquoted you. My ex cheated on me and that was it for us. It started with messages as soon as I suspected I started to detach, and then when I had the proof I left. I don't mean to add to the confusion, but just wanted to share my thoughts.