How do you get over the fact that your boyfriend cheated on you?

Yesterday morning i received a message from a girl (my boyfriend had said he would sleep with her to one of his buddies a few weeks ago) . turns out he had phone sex with her twice!!! he was obliterated drunk both times (i have the recording of one, although it’s NO excuse) he told me she means nothing and he’s deleted her on all platforms. i love him so much, but i’m so heartbroken. i forgive him, he cried and begged for forgiveness and told me he is an idiot and he’ll start loving me the way i deserved. how do i get over the pain and the insecurity?