I Feel Like My Dad Ruined Our Family

Hello, this is not exactly a confession about myself, is more about something that happened in my family recently, first of I am Chloe I dont think my name matters much, I am 16 but the conffesiion didnt let me put my real age and I live with my mom and dad, well, to be direct, my mom found dad having sex with a guy recently, and now they or more like she spent all the day talking shit about him and being angry at him in general, and I understand that but I am a bit teared by the situation, I want to sympathise with both but I really feel like my dad just ruined the family, he have been always caring even now, it may be selfish of me thinking this way,but , I would have liked if he could have keep things as they were even if he was actually gay, they always seemed to be happy together, my mom was kinda the moving force in the family taking the decision but dad always looked happy with this, but he talked to me and told me he was stressed by her for a long time, he is trying to makling things up with mom but I have found him calling that guy, he have the guy number apparently, I fear he might run away with that guy and leave me alone with mom who may become changed person for worse by this, I dont know what to do, sorry if this is not what you expected to find because of what is normally confessed, but thank for reading anyway.