Sex is so much more than getting hard. I am putting the drunks and druggies aside, as that is a totally different matter.
Seems like your focus is on getting off. If they are upset with you about not getting off then it sounds like they are not into the sex to begin with. Focus less on insertion and more on other forms of contact and activity. If it is good, you don't WANT the other person to get off, because that spells the end. And just because you can't get hard doesn't mean you can't ejaculate. For some it takes a little more work, and for some the real pleasure doesn't even come from ejaculation anyways. If they seem like they just can't get off start asking what really works for them when they are by themselves. They probably have found some other pleasure zones that you may have never thought of before.
And as always, if you are expecting something be upfront about it. Sex is a bit like shoping - you need to find someone who is selling what you need. Everyone is shopping for somethg different - there is someone out there with what you are looking for, and conversely someone out there is needing exactly what you are offering.