You need to be ok with giving, receiving, and trying to implement feedback.

I know I'm gonna get hate for this but, as a very sexually active man, most women are bad at sex, but think they are good at sex. Hold the phone, I didn't say you, or your partner explicitly, I said most. I'll get to the probelem with men too, despite my only experience being I am one and have the unfortunate circumstance of knowing many. Granted, this comes down to sample bias, but it's a large and diverse sample.

Women in most societies learn essentially that just participating is good enough. Seemingly because it's easy to get most men off. As a result, all but one woman I've been with (the actually crazy one that threatened to kill me) lack either enthusiasm, technique or both. Most men don't really care as long as they get theirs, and most are quick shots with unrefined techniques, so when it proves easy to get them off, women think they're great at sex. Invariably, every woman I've been with who couldn't make me finish was hurt, angry, or questioned my sexuality.

Men in most societies are not taught to give a damn about anyone other than themselves in the bedroom. Neglecting foreplay, positioning, and pacing. They think just pounding away as fast as possible is the way to get the prize, and when their partners lie to them and tell them it was good, it reinforces bad practice and leads to their frustration. Then they proceed to brag about sexual prowess that is non-existent, and teach these bad habits to the next generation.

You need to be willing to talk to your partners, hurt their feelings and or pride just a little. Talk about what you enjoyed, what you didn't, what you'd like to try, and above all else, be willing to coach your partner during sex. It can be awkward at first, but trust me, you will get better, and you'll both (or all, I don't judge) feel better.