Cheater

So around march or April my boyfriend made a mistake and didn't end up telling me until like July. (This is a long distance relationship) he told me while I was gone for like 2 days he got extremely drunk to the point he didn't know what he was doing, and he sexted this girl. He told me in July and he was devastated. He cried for days Bc I was ignoring him and he didn't want to lose me. He promised he'll never do it again and since he was shit face drunk and didn't know what was happening that was why he did it. He said he never wants to be that drunk again either. I feel I can trust him and stuff but it's always better to get an outside opinion. Should I trust him about it? Will he cheat again? Or was it just a minor mistake? Please help!!! Also since I was gone for two days and he was drunk two days straight, he sexted her continuously just those 2 days. then when I found out I forced him to tell her he has a gf and he's not talking to her anymore. If you need more details let me know!