I'm going to echo what a lot of people are saying here except I won't necessarily say you should leave him.
He was obviously sexting with someone and they got him to send nudes. They were probably blackmailing him for money. Depending on what you define as cheating, he may have been cheating on you. At the very least, he is lying and being inappropriate with a stranger. Deleting messages before you can see them is so suspicious.
hiswife10 t1_j6or4cl wrote
Reply to My (f24) husband (m25) sent nudes to someone else. by [deleted]
I'm going to echo what a lot of people are saying here except I won't necessarily say you should leave him.
He was obviously sexting with someone and they got him to send nudes. They were probably blackmailing him for money. Depending on what you define as cheating, he may have been cheating on you. At the very least, he is lying and being inappropriate with a stranger. Deleting messages before you can see them is so suspicious.