After lunch, Mark followed us back to the beach. We’d had enough sun for the day, so he grabbed one of the large folding beach umbrellas and used his manly muscles to make a little shade for us so we could watch him play volleyball.

At one point later on Sophie called for a coed game, so Bethany and I took off our cover-ups, put on some more sunscreen, and bounced in to play on the girls’ team.

I noticed Mark watched us both closely, but wasn’t obvious about it. He didn’t want to blow his cover as our secret boyfriend, but I was pleased he couldn’t seem to keep...