No One Knows I Saw My Daughter In Law Cheating

This happened about five years ago. When my husband died in a car accident, my son and daughter-in-law insisted I come live with them in their huge house for a few months. I didn't need to -- I was financially secure and independent by nature even in grief, but I figured it'd give me a chance to spend some time with my twin grandchildren who were six years old then.

My DIL was having trouble staying on a fitness regimen and hired a personal trainer not long after I arrived. The trainer was an middle aged man, a lot closer to my age than my DIL's. He was still fit of course, and nice looking, but wasn't knock-out handsome. Everything seemed above board. My son or I were almost always there when he'd come by. One day, though, my son and the kids were gone and my DIL assumed I was too--I'd parked my car in the garage instead of the driveway where I usually left it in the daytime.
I'd been taking an afternoon nap when I heard a noise coming from the downstairs room where my DIL exercised, and it sounded like the usual visit from the trainer. I didn't think anything of it. I padded downstairs to get a snack. When I was halfway to the kitchen I thought I could hear whispering and the sound of kisses. I crept toward the room where they were. The room entrance was offset and there was a large mirror on the wall that allowed me to see them without too great a chance of being seen. I could hear my DIL say "No, stop, I can't do this." But she wasn't pushing him away or resisting him at all as he undressed her. In fact, before I knew what was happening, she was returning the favor and helping him undress. The trainer picked her up in his arms and carried her to a futon that was across the room. She moaned and whimpered, "Noooo.........." even as she spread her legs wide and used them to capture his waist as he mounted her. She began hugging and caressing his back once he started thrusting

It's still hard to describe everything I was feeling. I was mad as hell at my DIL, madder at the trainer, but I was jealous too. I hadn't been ploughed like that, so to speak, in years. I found myself masturbating as I was watching. I can't really remember how long this went on, but that trainer was a very virile man for his age. He made my DIL orgasm at least once, and then he pulled away and came all over her abs. I shook myself out of whatever kind of trance I was in and quietly crept back upstairs before they had a chance to get up.

I went back to my room and waited until the trainer had gone. I came downstairs rubbing my eyes as though I'd just awakened. My DIL, still naked and drying her hair after stepping out of the shower, gasped and dropped her towel when she saw me. She said she didn't know I was home. She asked where my car was and I told her I'd parked it in the garage. I just went on talking about what a good nap I'd had, and told her not to let me sleep so long like that again.

I don't know whether she thought I knew or suspected anything. The trainer never returned and she didn't hire another one. She told my son she didn't think having a trainer helped much anyway.

I never told a soul what I saw. Why? Number one, I still think my DIL loves my son, and I know he loves her. They get along great and they adore their kids. Number two, I succumbed years ago in a way not too different from my DIL, and I guess I don't blame her as much as I ought. Number three, I'm not going to take any part in breaking up my grandchildren's home. Maybe my son would get custody, maybe my DIL would, but I stand a chance of not seeing them as much as I can now. That's selfish on my part, but also, I truly don't think my grandchildren would be better off being shuttled from one parent to another or possibly being raised apart from each other.

Do I feel guilty that I'm keeping this from my son? Of course I do. But I'll bear it. If I'm wrong, I'm wrong.