How do I feel less insecure?

So my bf and I have been dating for 5 and 1/2 months and I’m totally fine with him touching my boobs (hand under bra, just my boob and his hand). For a couple of times when we were making out he would pull my bra up so our chests would touch. I didn’t mind it but when he looked down at my boobs I got kind of embarrassed so I covered them with my hands. I think it’s a mix of being insecure about the way that they look and being told to be modest my whole life. I told my bf that I got a weird feeling/ I felt insecure and he told me that I shouldn’t feel insecure and that boobs come in all shapes and sizes and that he loves me regardless. He also said that it makes him sad when I tell him that I’m insecure about my body because I can’t see how beautiful I am. I want to not feel weird about having him look at them, does anyone have any tips?