Is a sexual "bad fit" a dealbreaker in your relationships?

I was reading a question recently posted on Fluther about “preferred” penis lengths and it made me wonder about this: for those that have a “preferred size”, is not having the “preferred size” a deal breaker? Say you liked everything else about the person a lot, “sex day” comes, and you find (ex.,) the woman is too small for the man, or the man is too small for the woman, or maybe the man has erectile dysfunction, or the woman…etc. Would you give up the relationship? Would there be no chance for a lifetime commitment? I’m looking for male and female responses.