There's no easy answer to this. All I can tell you is that he's already having sex with you, and he thinks you're hot. Men are far less critical of our bodies than we ourselves are, especially when they want to have sex with us.
And if they want to, then we can't look that bad!
In all seriousness, sex is messy, looks funny, and sometimes smells a bit off, but it's fun! That's what makes it fun! It's not as perfect and beautiful as in the movies, but it's a lot more fun!