This tmi but..

The other morning my so and I were in the shower and I was washing me hair and my so was quite (which he never is) so I turned around to see what he was doing and he was jacking off to my ass than when he was about to finish he finished all over my butt and back. Should I feel disgusted or flattered? Idk why he felt he needed to jack off instead of just having sex with me? Idk what to think about that whole situation