The thing is @Welshie2 its easy for us to say LTB but not so easy for you in the moment.
A lot of us have been through it, if not the car crash your H has brought, certainly cheating exes and have come out the other side healthier and happier for it. I have never seen a woman on here (or in RL come to that) say that they wished they had stayed with their cheating ex.
Right now you are clinging to the fact that what he says might be true. That it really was just a bit of banter that maybe went too far, and that someone is trying to stitch him up. So if he doesnt lose his job then that will prove he wasnt shagging at work etc, and maybe, just maybe things can go back to how they were. Its scary to think of the alternative of taking apart your life, family, home etc and starting again, I remember that feeling well.
But the problem is that it can never be how it was before. The cake cannot be unbaked. Its happened, you know and saw it all with your own eyes. You will always have that knowledge at the back of your mind. You will always remember that while you were going out of your mind with worry and confusion, he was sunbathing, and planning BBQs and holidays. You will always remember that he didnt bother looking for another job because he was so arrogant, never mind the worry it was causing you. You will always remember how he didnt give a single tiny solitary thought about you, how you are feeling and how this is affecting you. That knowledge, no matter how hard you try to squash it down, will be the gremlin at the back of your mind.
Its so easy for us to forget that this is your real life, it isnt just words on a screen. I think you could really do with some RL support and if you dont feel comfortable with friends you could try Relate or similar.
Take care.