How important is sex?

for me, sex in a relationship is a benefit, not the basis of the relationship, as my ex thought. he thought that if we never have sex the relationship will never, ever work. he didnt want the relationship to develop more so we didnt rush into things, he just wanted me in bed, which i found as a huge turn off.

however, if there is completely no sex in a relationship, then there can be tension involved, which can then break a relationship, if with certain people.