Forum purging and the female orgasm.

You just have to enjoy yourself and make sure your partner enjoys herself.

Orgasms are only a strict necessity during sex if you are aiming to make a baby instead of having fun.
I have a number of times. And sometimes I don't cum. Not usual, but sometimes one has to take a break and maybe try again later. And other times, I may cum but keep going and then stop before cumming a second time.

Orgasm is not a necessity. It's nice, but not required. As Spurious said, the only time it would be required is during procreative sex. Trying to have a child, as it wouldn't work so well if no little spermies made an appearance for the mad dash down the channel. ;)