I caught my husband in a "white" lie, what should I do?

He has always been loyal and a hard working family man. We have been together for 12 yrs. and have had our ups and downs but are now happier than ever. He rarely goes out with friends, so recently when he wanted to go boating on the river with one of his single pals I didn't think much of it. After telling me he would be out for a few hours, he was actually gone for 10 hours and didn't call or answer my texts or calls. He showed up at 10:30 at night drunk and obnoxious. He adamently swore that he wasn't around any women and that he didn't even talk to any women, I had a feeling he was lieing about something but let it go since he was drunk. So the next day when we discuss the situation again he admits that they were partying on a beach and that his buddy was picking up women but that he was totally innocent and had done nothing wrong. I have tried to get over it but I don't understand why he lied in the first place? Married, gone all day, no phone call, and lieing about wether he was or wasn't around other women when he was drunk. Sounds fishy to me, but now he says he is the one hurt because I don't trust him. What do you all think?