My ex-girlfriends brother is my son
I dated "Beth" for about 7 months my senior year of High School. I spent a lot of time over at her house and got to know her mom "Amy" pretty well. Amy had beth when she was 16 and was only 34. She wasn't married but had been dating a guy for about 5 years.
Other than the occasional mild flirting nothing serious ever happened with me and Amy while I was seeing Beth. Our relationship kind of ran it's course but me and Beth remained friends and I would still go over to her house to hang out.
About 9 months after I graduated I was over at Beth's place and her mom was getting ready to go out for one of her friends bachelorette party. She was wearing a form fitting red dress, makeup and had her hair done up. She looked absolutely stunning. I told her she looked amazing and she did a little spin and said "You like this". I said I did. Beth just laughed and said we were gross. I wasn't out of the ordinary for us to joke around like that so that was pretty much it at the time. Amy left for the party and me and Beth hung out and watched movies.
Me and Beth were just finishing the last movie when Amy got back around 1. She had obviously had a good time at the party. She sat down and watched the last 15_20 minutes of the show with us. When it was over Beth said she was tired and headed off to her bedroom. I said I should probably get going as well and started to gather up my stuff.
As I was getting my keys from the kitchen table, Amy said you don't have to leave. Being an oblivious 18 year old idiot I said it was getting late so I should head out. She moved closer to where I was and said "I think you should stay here" while she did a more wobbly version of the spin from earlier that night. Even my dumb ass got that hint and I was instantly rock hard.
I asked about "Tom" and she said they had been broken up for a few weeks. That was all I needed to hear and I stayed the night. Me and Amy regularly hooked up over the next 3-4 months and it was one of the best times of my life. I had only been with two other girls at that point, one of them being her daughter, and she taught me a lot about pleasing a woman.
One night after we were done she told me that her and Tom were getting back together so we would have to quit hooking up. I was pretty bummed but I always knew it wouldn't last forever.
Fast forward 26 years; I get a friend request from Beth on Facebook. I accepted the request and about a day later I get a DM from her. All it says is "Did you fuck my mom?" I just sat and looked at it for a while contemplating if I should answer. Eventually, I decided it was 26 years ago so while she may be upset it was ancient history. I replied that me and her mom had seen each other for a few months well after we had been just friends.
A couple of days go by and she sends me another message. I was kind of expecting to be completely cussed out but what I got instead completely floored me. Beth told me that her mom had died from cancer a few months prior and on her death bed told her that her brother was actually my son. She said Amy knew it was my son because she was late when her and Tom got back together. She never told anyone because Tom was so excited to be a father but the Drs estimate of how far along she was puts it a solid 2- 2 1/2 weeks before they got back together. Beth was the only person who knew the truth besides me now.
We never used condoms during sex. Once again, me being a dumb 18yr old I just assumed she was on birth control. She never asked me to pull out so unless she was swallowing I just came in her.
Her and Tom got married and Eric was born a few weeks early. They had remained married until Amy's death and Tom had been an excellent father to Eric and grandfather to Eric's daughter Amanda. She said her mom thought I should know.
Honestly, I'm at a loss what I should do. While I would love to get to know my other son and first grandchild; there is a lot of potential for this to hurt everyone involved. Beth thinks we shouldn't tell anyone. Is this the right thing to do?