Men with pretty girlfriends/wives, how much does it really matter over time?

I was recently having a conversation with my friends, and I was of the opinion that men tend to give very high weightage to how pretty a girl is, but once you start dating them, you soon get so used to it that the looks dont make any difference.
Few of my friends didn't seem to agree, and said that although character matters more, looks make a huge difference.
So yeah, as the title says, men who have been with girls that are considered conventionally attractive, how much did it actually matter over time?
Edit: just to clarify, i understand the importance of finding your partner attractive. The question is more along the lines of whether it makes a difference to go much beyond that and being with someone "more attractive than the average" because ive seen lots of guys trying for that and getting respected by other ppl just cuz they have extremely pretty partners.


Source.