"I am 58 and about to be separated from my wife. My mother-in-law is 80, and I have been attracted to her for about 30 years. I have this gut feeling she is attracted to me, too. How would I go about telling her how I feel? She is widowed and probably hasn’t had sex for about 20 years. If I could just cuddle with her sometimes, that would be enough satisfaction for me. I should mention that I love my wife, but she wants to separate. I still can’t help being attracted to my mother-in-law. I have always been attracted to more mature women."
I’m not going to help you tell your mother-in-law that you’re sexually attracted to her, because I think that would be a bad idea. Sure, there’s a remote chance she feels the same way about you, but there’s a much greater chance that she doesn’t. You’d potentially wreck your relationship with her and any chance that you and your wife could reconcile.
You say you have a “gut feeling” mother-in-law feels the same way — based on what? Does she act seductively towards you, or is she just friendly with a flirtatious edge? You figure she hasn’t had sex for 20 years — has she confided this? If not, you don’t know what happens in her private life. Even if she’s desperately horny, she’d likely not choose her daughter’s soon-to-be-ex-husband.
We can’t control what sexual fantasies turn us on, and I’m not judging or shaming your erotic fantasy. But I think this is a fantasy best kept private for your solo self-pleasuring.