Hi Susan,
Something is fishy here..... it' a very strange story.... very suspecious as well.... You are not crazy at all..... on the contrary, you are very normal, anyone would react in that way under those circumstances. To many holes in that story.... much grounds to believe he is cheating as well (no offence, please). You need more hard evidence. How about hiring a PI (private investigator). Keep on being on alert. Join him as much as you can. Show him you don't "buy" his story. Try to discuss it with him, tell him 30 years of marriage are being in stack / risk.
Best regards,