It takes me forever to cum! :/

Am I the only woman out there that takes foreverrrrr to orgasm?? It is SO frustrating sometimes! My man makes it his goal to make me cum first which is amazing but lately it's gotten to the point that I just tell him to cum because we are both so exhausted. We have tries multiple positions and I have a couple that used to do the trick right away but just don't cut it anymore...last night he started talking dirty to me and it triggered something and BAM. Orgasm. But then we tried the same thing today and ....nothin. Well I mean something. But nothin lol ...help? Suggestions? Advice?