bf looked up his female coworker

this is probably childish of me but still. my bf and I have been together 5 years and tonight I was with him and we were talking about the future and what not. He has one female co worker at his job that he tends to bitch about since she isn’t a very good worker, but i still think she’s pretty. My boyfriend works afternoons so he’s always up till like 4AM watching movies and stuff. But Last night , or should I say this morning, he looked her up on Facebook. He didn’t friend request her and This is the first time he’s searched her so it’s not like it’s an ongoing thing, but he definitely looked through her photos and stuff. How should I feel about this. I just don’t like that it was at like 3:30AM.