u/Ludichri5

Always think I’m small

Hi, I’ve never discussed this but reaching out to share my story which has scared me for years!
I was told many years ago that I have a small dick. Yes just those 2 words have caused me a lifetime of low self esteem and messed up relationships (hope in posting in the right group for this issue). The relationships not lasting has always been down to me thinking my partner has had bigger and prefers bigger so they will cheat on me and leave me! Has anyone ever felt like this before?
I’m 5,11 about 215lbs, not fat, train weekly, big arms, chest, legs. Never had trouble getting attention or picking up girls.
But I feel like I disappoint them sexually even the ones who say different.
How can this mindset be changed so I can be content with what I have?
Any advice would be great thanks