Why is he with me?

B • Just a girl trying to fit in

So I am 5'2" and 286 pounds. My boyfriend has showed me pictures of other women he has been with, and most of them seem to be skinny, taller, and very pretty.

Why has he been in a relationship with me for the past two years if he could have a better looking woman? Does this mean he probably hasn't been faithful to me?

Thank you.