My[21F] boyfriend[21M] addmitted to watching his friend mastrabate

Sorry earlier i copied the wrong post into here sorry 😅 But this morning my boyfriend admitted this, what happened was him and her was playing roblox it was normal at first until he started hearing moaning noises he asked her what she was doing and she turned the camera on to her nude mastrabating. They have done sexual things in the past before he met me so thats why she was comfortable doing this but he didnt tell her to stop like he should have he screenshoted it and just watched. He said he was kinda shocked and during his heart was pounding and his chest felt heavy. Apparently she knew about me before doing this so I told him i didnt want him talking to her and he blocked her he seems really sorry about it and said he would never do something like this. I feel hes being honest with how fast he admitted it and how emotional he was (this is the first time i heard him crying) I dont want to break up, how do i move on from this?