Please help me how do I tell him without hurting his self esteem even more?

I (38F) have been dating a man (44M) for about 6 months now. Before this, we were very close friends for nearly 4 years.

He has a difficult past, he was emotional abuse from his ex-wife, who often rejected him (especially sexually) and later cheated on him. It’s understandable that these experiences have taken a major toll on his self-esteem. Since we started dating, I’ve done my best to reassure him that I’m not like his ex, and overall, we have a great connection, including a good sexual relationship.

However, issue I’m having is that he sends me unsolicited explicit photos quite frequently of himswlf—several times a week. I know this is a way for him to seek validation, and I love him dearly, but receiving these pictures has started to make me uncomfortable. When I open my messages and see them, I’m often unsure how to respond.

I know this sounds a bit absurd, but I really need advice. How can I tell him I’m uncomfortable with this without hurting his feelings or making him take it personally? I’m aware his past trauma and self-esteem issues are at play here, but I still need boundaries around this. Any advice on how to navigate this would be appreciated. Thanks in advance, ladies