Too late for me, but the following advice was recommended to a young man about to get married.
Before committal, have your prospective wife sign the following oath.
I, THE UNDERSIGNED, AGREE THAT:
1. In the unlikely event of my not having an orgasm after you've drunkenly rolled on top of me and pumped away for five minutes, wheezing like an old man with emphysema, I shall politely fake one. It will be a really good act too, with me saying stuff like "So THIS is screwing!" and howling like a cat that's had it's tail stood on..
2. Should your mother show me any photos of you as a child, like those ones taken at your auntie's wedding in which you are sporting a velvet bow tie and a pudding-bowl haircut, I shall make no comment. Ever, or even look at you in a way that suggests they are at all "funny".
3. I fully understand that a woman's main role in any relationship is to take the blame. So when you stub your toe in the bathroom or your football team lose, I agree that - by some complex scientific equation incomprehensible to woman - it will be my fault. Even if I wasn't there.
4. Whenever my friends and I get together for a girlie chat, I will tell them that you are better hung than a large-balled Himalayan yak.
5. I will also mention this to all your friends. A lot.
6. After sex (which I will NEVER refer to as "making love"), I will not expect you to cuddle me for hours till your arm goes dead. Nor will I let my hair annoyingly get in your face.
7. I will never, ever, give your penis a "cute" nickname.
8. In bed, I will be as keen as mustard to try any novel sexual position you fancy. Especially ones where I do all the work and you just lie there, grinning.
9. I will ruthlessly interrogate my attractive female friends and inform you if any of them have the slightest bisexual tendencies. Then I’ll invite them around for dinner and hide their car keys so they have to stay.
10. After we split up, I will never sleep with any of your friends or colleagues. Or anyone else you have ever met. Or, may one day meet. And, if men attempt to chat me up, I will solemnly inform them that you have "ruined me for other men".
11. I understand that mechanical objects like cars, computer games, and remote control devices are beyond the comprehension of women. I will only make a fool of myself if I attempt to operate them, so you're in charge of the lot. Except for the iron, the vacuum and the washing machine, of course.