i have bad news

guys so i found out my boyfriend was cheating on me for the 3-4 months we were talking :(, i texted the girl he was with while he was with me a really big paragraph apologising and i told her im ready to send her any proof she needs. i feel horrible for myself and her like bro omg. hes literally tearing her apart, she knows he was cheating and still stayed (me too but i thought he stopped LMFAO). i feel like she needa have some self respect and leave him and work on herself but like i cant control her thats not my life also i miss his 7incher and when he would call me baby