Why MGK declined to have his pic taken with McGregor

Since MGK was with Megan Fox, McGregor would have asked the couple pose with him. MGK was probably being the protective boyfriend for Megan Fox. With his girlfriend dressed provocatively in a sheer dress leaving almost nothing to imagination, why should he allow another man to have private photos taken of her? On the other side of the coin, why would a married man desire to collect personal trophy pictures of a woman who’s taken? That’s food for thought.