The people who would be deemed "less-attractive" by culture-centered standards find suitable mates, too. Just like some jerks find suitable mates. Boring people find suitable mates. Communists find suitable mates. With regard to the physical: It really doesn't matter how "ugly" a person is by society's standards.
Anyone can find a date.
Anyone can get married. The question that should be asked is why a person doesn't feel like they're good enough. Many physical "problems" can be fixed. Bushy eyebrows or uni? Wax.. or pluck (old school). Unruly/frizzy hair? Hair product... or moisturizer if you're ghetto. The sad truth is that no matter what anyone tells a person who thinks they're ugly, that person will keep believing they're ugly until the day of their demise if something does not change. We have to see in ourselves the positive things that we bring to the table.. because each and every one of us does. So you have a cleft chin. So what. John Travolta has one and many women consider(ed) him to be the ultimate sex symbol. Why? I don't know, but he is/was for those women!
Truth is, you will never be happy if you keep finding faults within yourself and nothing more. Are you imperfect? Heck yeah, you are! But guess what, so is every other person who has ever lived and ever will live (except Jesus

).
So here are your options: Be happy with who you are, faults and all. Try to
change a few things you
don't like about yourself; see what works/what doesn't. Or just be prepared to be miserable for the rest of your days. Because I'm tellin' ya... even if you DO get married and still feel so ugly inside, what is it really worth if you still feel so awful about yourself?