My mom has/had an affair with my uncle

Throwaway since my siblings would know my other account

So I (F23) discovered that my mom has/had an affair with my uncle and I can’t really tell anybody. Not my siblings, not my cousins, no one in my family.

I was logged in on her email account, since she was getting an important document for me and I wanted to see when she got it, but then I found hundreds of mails between her and my uncle from November 2011-2020 saying stuff like "I love you so much" "my angel" etc.

. I’m not sure if it started before the first mail in 2011 and if it really ended in 2020 or if they’re communicating via another platform or method.

My mom divorced my father in spring of ~2011 (she was already checked out of the relationship at that point,

and she planned our move and everything before then so we could leave in the summer.

My siblings were already moved out since they’re older) and my uncle was and still is married to his wife/my aunt. And I honestly get it.. I was confused all my life why my uncle and my aunt even got together since they’re so different. And I also get why he can’t divorce her… she’s kind of really dependent on him, she "can’t" pump gas on her own and it always has to do one of my cousins or my uncle... and she is used to his wealth.

When I saw those mails, I kinda put everything together since I already had a hunch because I, by accident, saw a message on my moms phone under an alias but it pointed to my uncle. I was a young teenager at that time and since I didn’t know for sure I kept it to myself. He also visited us like once every 1-3 months "when he was in town" and when I came out of my room to say hi, they were sitting suspiciously close to each other. Now that I think about it, those visits were after 2020.. . Also my mom often went on a trip with a girlfriend and I was always confused why she would go with her since they don’t talk that often/never talk… well I found emails indicating that my uncle went with her. I told my therapist today since I had to tell somebody and he questioned if I might be his child… and honestly there could be a chance. I was born in 2003, so they could've had a one night stand (or more) back then… all my siblings are born around 1990, same with my cousins, but I’d rather not go down that spiral.

I’m a little overwhelmed by all this and I can’t tell anybody since it could break the whole family.. maybe somebody also knows but I wouldn’t know who and I don’t want to risk it.

Should I tell my mom that I know? What would I say? She would know that I kinda snooped her email account (she knew I was logged in for the document) and I have no idea how she would react. My therapist said I should speak with her about it, but I’m really anxious and don’t want to be an accomplice, if I’m not one already.. . Should I stay quiet and suppress it as best I can? Or tell her I know in a few years?

I don’t know what to do…