AITJ for letting my mom cheat on my dad and pretending everything is normal?

My mom (42F) has been cheating on my dad for years, almost a whole decade. I first found out when I was around 7. At the time, we were sharing a house with another family that we weren’t related to.

One day I saw the other family’s dad, Jacob, making out with my mom in the kitchen. I panicked and ran away. Another time I walked in on them again this time doing the deed while my dad was out fishing and Jacob’s wife was shopping.

About two years later, the other family found out and we got kicked out. After that we started living on our own. My dad forgave my mom because he believed it was the first time it had happened.

But even after all that, she kept cheating with several different guys, including Jacob. Jacob has a car, so whenever my mom and I need to go somewhere without my dad, she calls him and he drives us. She also meets some of the other guys at restaurants or other places, and sometimes I’m with her when they meet up n my moms pretty open to me ab cheating. Plus shes gotten caught prob 2 more times but dad still chose to forgive her i have a feeling its for the sake of me n my sister.

I’ve known about all of this for years but I’ve never told my dad. Part of me wants to tell him because I feel guilty keeping such a big secret. But another part of me is scared of what would happen if I did. It would probably affect me and my sister a lot. Our family isn’t the most financially stable, so if my parents split up we might have to move far away or change a lot about our lives. I’m in 10th grade right now, so that kind of change would really affect me too. Because of that, I’ve stayed quiet even though I’m not sure if that’s the right thing to do.

So Reddit, AITJ for staying quiet and letting my parents marriage continue like this all these years?