I caught my mom and uncle having sex. A little over a year ago I (19m) came home to what can only be assumed as my mom Bec (40f) and my uncle Alex (50m) having sex. (All names are fake and ages are in standing time so minus one year to all ages for the back story). I should also note that they are half siblings (share a father).

That night I was supposed to be staying the night at my aunts house with my sister Lizzie (8f). When I pulled up to my house I found the house dark and my uncles car in the drive way. After gathering the items I need I see light coming from under my mother’s door. As I go to turn the handle I find her door is locked. With my stomach now churning I bolt out of the house. I get into my car shaking like I’ve seen a ghost and my partner is very obviously concerned.

As time goes on my uncle starts officially living with us. As there is no spare bedroom for him, he is living in the living room and sleeping on the couch. My mother starts also sleeping on the couch with him. (It is a modular couch so it is equivalent to a king size bed). As time continues to go on I find instances where they are too close or too flirty.

Fast forward to about two weeks ago. At this point I moved out about a month and a half prior. My sister now stays with me on Thursday nights. My sister brings my mother iPad over so she can ft her friends before bed. Friday afternoon I remember I have the iPad still. My mother receives all her texts from her phone on the iPad as well. I decided to go and look through her and Alex’s texts.

After about an hour of scrolling I find a long conversation between them covering all the bases of their relationship. Including the longevity of the relationship, drugs, sex, the type of sex, toxic behavior, and the fact that they are very clearly siblings. In previous texts I would read messages from my mother with things along the lines of her not giving sexual consent, but in recent texts it is shown that they do in fact have sex.

So what do I do with this information? I have intentions of fighting for custody of my sister in the future to provide her with more stability. On one hand I want to keep this information hidden in a safe place to bring to light when I am finally able to get a lawyer and start the custody battle, or if I should find a family therapist to talk with my mother about it one on one. Reddit I need your help.