At this point, I'd almost be relieved to find out there was some explanation. If it is an A, I would guess it's an EA. I have asked him point-blank several times and he has said no--even in front of our MC. She has also indicated to me in IC that it seems unlikely.
I know, it seems like I am in denial.
Although many are having affairs, not all are. I don't think it's "denial" if you have no evidence to the contrary. A lunch meeting that you are told about is not such evidence. You've asked and he's answered and I think it would be counter-productive to ask again.
I know what you mean that it would almost be a relief to have an "explanation" - but MLC probably does explain a lot of what is going on in your sitch, even if there is no OP involved.
me: 47 H: 48 he has 2 grown sons M 1995(my 1st, his 3rd) hit iceberg 6/07 S 9/26/07 before now