I could be completely wrong, and much as I applaud the 'girl power' stance and support and appreciate you want to hear that, I want to offer something else.
I agree it's a bit creepy and weird photographing some random woman, however I think it's a symptom of something else.
I don't think it's just as simple as she was a 10 and you are a 16, I think that is you transferring your own insecurities onto him, and then imagining that he thinks 10 is better than 16. 10 is different, 10 is pretty, but it is not better, and it doesn't mean he prefers it. Have a bit more confidence in yourself, like someone else said, he chose YOU!!
Try and take a step back and analyse things from his perspective. How are things at home? Are you guys getting on? Do you ever have sex? Or is all the focus on the babies/kids and he's not getting any grown up attention and is feeling rather hard-done-by and pent-up?
I'm not justifying pervy behaviour, but I just have this image of a guy who's feeling sad and lonely and saw a pretty girl and got a bit carried away...we've all had a dribble over 'that cute waiter' at some point so don't blow it out of proportion, hurtful as it is.
There is also alot of pressure for holidays to be magical. Yet all the strains from home come with you and often blow up as it's the most time you've spent together in months!
Rather than confronting him with 'how dare you take that photo' type attack which will put him on the defensive, maybe try snuggling up and saying 'I realise you've been missing me, maybe we could do something nice together, watch a DVD or something?'
I'm sorry if I've read this totally wrong, and if he is just being a git, but I just wanted to offer a different angle.
Good Luck, I hope you guys get it sorted.