I'm curious what she considered "seriously dating". I think while I was at BYU I was dating a few girls more seriously than others, but they often overlapped. I wasn't in a serious defined relationship with any of them, but every couple of months I would go on a hike with them or go grab something to eat. Most of the time we were still investigating each other.

I think with my wife, once we started holding hands and kissing, that is when I stopped asking other girls out. But that was after we had a few initial dates.

Anyways, what I'm saying is, if she likes him, she may want to consider giving him so grace for the photos and reassess where they are. Maybe he enjoyed his time with the friends and ex-gf, but in reality he was missing your girl.