my dad is cheating with three other women while legally married with my mother. what do I do

My sister found out about this by unintentionally stumbling over gifs on his social media used for flirting and couples in infatuation, since our parents weren’t as close as they were before and never flirted at each other as of recently, she raised suspicion. She got aware of this situation and found out our dad was constantly calling the other women wifey names and flirting with them on social media, after she was sure about the situation, she showed me the chat history. Specifically, one of them he had an extremely close relationship with for at least 3 years, with the other few (we’re not sure the exact amount there could be many)  just partners for sex. It’s been 2 years since my sister found out, we’re both unsure if our mother knows this or not. this absolutely disgusts me and this changes the way I view my father: instead of a responsible grown man and a family leader, I sometimes see him as a horny bitch addicted to sex without any baselines and boundaries of his own actions, while on the other hand, he attempts to portray himself as a hard working, nice and, responsible father on us (i dont mean to be offensive but these are my very honest opinions, as if anyone would see a cheating man). my sister and i have discussed whether we should expose his ass or not, specifically talking to him about our concerns, or snitching to our mother about his behavior, but since we rely on him financially for our tuition for our education and our future college expenses, we've decided that it is best to not expose him as of rn as this could potentially irritate him (i am 16 my sister is 12 we found out 2 years ago). but my dad keeps being a dick and constantly sleeps with other women. i was once irritated after my father and I got into a fight, and attempted to expose this thing without directly addressing this event. but after it he just simply pretended that nothing happened, or if he was unaware of this thing. However he did somewhat feel the intentions, and responded to me saying that I cannot control him. i genuinely think this thing is fucked up, as he is Irresponsible to my mom and my entire family, and sometimes i wanna beat him up badly bc of this. We want to do something cause this entire thing is making us extremely uncomfortable, as our father shows no intentions of changing or even a sense of guilt. Help me think of a solution