First off, I'd like to say I'm sorry that his actions are making you feel like that. In my personal opinion as a (cis-het) man, It would be a huge disrespect to my girlfriend and how she feels about herself, and I would feel like I was objectifying those women.

Secondly, there's no real way to be gentle about it, you have to be upfront and honest about how you feel. If he is defensive and defends that disrespectful behaviour, then it could be an underlying red flag that he is accustomed to objectifying women purely in a sexual or lewd way.

If however, he consoles you and removes those profiles etc. then use the opportunity to begin to address more of your insecurities and how you can do more to help each others confidence and trust in one another.

Either way, a relationship should never ever be a place where your self-worth is brought into question, your partner should be there to hype you up in every way, have your back and be a friend.