parent trouble

OK so I’m 14 ya young whoopee yay me. rite? well my parents are separated cuz my dad decided to cheat on my mom so ya of course i was pissed so was my mom when she found out.So its been about 6months and they both started to date others.Well sorta bcuz my dads is still dating the woman he was before. And I get a long with her. But my mom doesn’t know that I’ve been with her non of the less know that I’m her friend. She hates my dads girlfriend. And if she found out… i don’t know. Is it bad that I’m my dad’s girlfriend friend? I’m just happy that he’s happy is that so bad? What am I going to do bcuz i know my mom will find out sooner or later and i have a feeling she’s not going to bee happy.