I used to feel inferior in looks to my bf too. IkI'm attractive, but sometimes I feel like it's not equal. Still He's extremely attracted to me.
Looks are subjective. And plus, it's more about everything else than just looks. I'd rather the person I'm with love me for my personality more than my looks anyway (which he does), and maybe it's the same thing with their relationship. My bf loves me for everything, the whole package. Could be the same with them.
OR he could just be using Sam for his money. OR sam could be using him for a good ****. Who knows