Having just read and replied to the thread on Healthy Penis "anyone else have this problem" regarding a young man who indicates he's having problems climaxing during sex with his girlfriend (but not during masturbation), I actually assume that you're referring to each male and female partners. A link to that other discussion for reference:
http://www.lpsg.org/the-healthy-penis/62125-anyone-else-have-this-problem.html
Just by nature of this forum, I think many of us will acknowledge that sexuality is a lot more complicated than many people may appreciate.
The adage, "each person is responsible for their own orgasm" is oft-repeated and oft-believed. I think it has some validity, but doesn't acknowledge how complicated and intertwined each person's contributions are in a sexual encounter and relationship. In a fair relationship, each partner can and should communicate about what their desires and needs are and each partner can and should respond to the extent that they can. Very often, though, these aren't enough for too many reasons. Sometimes it is physical. Sometimes there are psychological factors beyond conscious awareness and control. Sometimes it's other things altogether.
As it is, the emphasis on orgasm as both a desired and necessary part of sex, I think, has the effect of skewing sexuality to a too-simple concept. Some people have had very knee-jerk and expected orgasms, but is their overall sex life really any good? Do they actually enjoy their partners (and do their partners really enjoy them) ? Some people seem to be anorgasmic, but yet will say and believe that they genuinely enjoy their sexuality and partners.
At worst, in some unhealthy relationships some partners may use their own (or their partners') orgasms and sexual preferences / desires to manipulate their partners in a passive-aggressive fashion. This actually includes this like withholding sex, or badgering for sex, or demanding/requiring sexual standards or otherwise reducing their partner as being inadequate or ungrateful (all done skillfully in passive-aggressive fashion).
Sex is more than just orgasm, though orgasm is considered a vital component.