Self esteem issues with SO

Km

He constantly feels like he isn't big enough but he is.

He was cheated on before by two selfish bitches who both told him he wasn't big enough.

He was my first. I love every thing about him including his penis.

How do I convince him of that? Anyone go through anything similar?

It's to the point he doesn't want me to get a surgery because I keep ripping when I have sex with him. He feels like after I will leave him because he won't be big enough.