My mom is cheating on my dad

I didn't know where to post this I'm sorry. I'm 15 and ever since I was a little girl I listened to my parents argue and one leaves the house for the night and comes back in the morning and just constantly fight. I always thought they should get a divorce but they're staying together just because they have kids. This is an unpopular opinion but you don't have to be married to be good parents, you know? Thats how I feel atleast. I recently discovered my mom has been cheating. My older sister plus my grandma knew but I guess I was late. I noticed she would randomly leave the house and she'd take showers and put on makeup right before she left. I saw her texting a guy once and they were flirting but she was shielding the phone since I was behind her. Then since she has me on life360 🙄🙄 everyone's location is on and she was at someone's apartment at 3 am. Then she turned her location off when my grandma called her and asked her where she is. I've been trying to look at my mom the same way but I just can't. It's not my business which is why I haven't said anything to her or my dad but I know if the roles were reversed my family would probably gang up on him. I just don't want this to cloud the way I think about her because the same way parents think their kids are innocent angels its actually the same way for kids too. No matter how many attitudes we catch or how mad we get our parents are like innocent heroes to us and I want to feel that way about my mom again but I can't and I don't know how to make myself push all of this out of my mind