My gf cheated on me on the past with herEx and rn shes going to a family sleep out in hotel and he's going, she said she wont do anything because she regrets what she did to me in the past abut she doesnt care for what i think, what should i do here?

Just an FYI, grammar and punctuation are your friends.

Your girlfriend cheated on you with her former boyfriend. She and her family will be at the same hotel as her ex. She does regret that she cheated, yet she doesn't care about your feelings? Have her go on the trip - ask her how it went. Based on her answer, you'll know whether or not she will wind up being an ex-girlfriend for you.