Would this bother you?

[SPOILEDkiwi]

I would let it go too. I find myself checking some of my fb friends' profiles more often than others if they have more frequent activity (posting pictures, writing notes, etc.). It doesn't mean I have anything more than a platonic interest in them. I also check people's pages frequently if I know they took pictures at an event I was also at, and I'm waiting for them to upload the pictures. Or perhaps she told him that she would be posting some pictures of a recent vacation she went on and wanted him to take a look. There are a million different reasons why he could be looking at a friend's fb page often, and if he's not doing anything else shady I don't think you need to worry.