Alpha might have slept with the student Omega in chapter 39 but we were never shown what actually happened from the time the Alpha was talking to the Omega at school until the time he came home at 4am, so it was left to the reader's interpretation. I think he cheated based on a couple of things but I know others have said they didn't think he did. Hopefully we get a flashback in future episodes to see what truly happened.
*correction: I think he SLEPT not cheated. The Alpha and Beta were still f buddies at this point so technically there was no cheating. Sorry.
Aside from the recent chapters, i want to know if the alpha had sex with omegas while being with beta?