What is your “goal” in having sex?
Are you looking for intimacy and fun? Are you looking to satisfy your partner?
This distinction is very important: recent research suggests that those who have sex for the former are much more satisfied than those who have sex for the latter.
I have to admit, this seems kinda obvious. When, in any situation, does doing something specifically for someone else not result in slightly less personal satisfaction? Okay, yes, those in service relationships will disagree, but I’m talking in general.
Sure, most of us do set out to please our partners sexually, but that is entirely different than having sex just to please that person. If that is the situation, you two have some issues you need to work through.