Small "man hood"

So to make a long story short..I was with my ex-boyfriend for 10yrs from ages 16-26..he's the only person I was involved with. That was 3yrs ago I'm currently in a new relationship which I'm happy with but his penis is smaller then what I was use to😩..I find the most common sex positions uncomfortable an not satisfying like they use to be..I don't want this to be a deal breaker because he's a great guy..but how do I get around this issue?