My moms cheating on my dad what do i do?

Ive seen the the text and heard the conversations. she visits him 3times out of the week takes him food gives him MY dads money because he doesn't have work and he has a wife and 3kids in mexico. she bought HIM a phone and pays his phone bill so they can talk. all she does is talk and text when my dads not around, she asked me if i had anything to tell her because i was always angry at her and i told her nothing, truth is shes making me grow hate for her and i shouldn't because shes my mom but i cant help it. the only reason shes with my dad is the other guy is a deadbeat that cant find work, cant support his family, and lives with other 5 guys that can barely find work too. obviously she stays with us because even tho my dad is stingy we buy everything we want, get our nails done, go to restaurants alot. idk wat to do i need help, i dont want to hurt my dad but i just cant help hating my mom!!!!!! PLEASE HELP "/