What do it mean when you don't have regular periods but whenever you and your partner have unprotected sex and he nut in you two weeks later your period comes on??

Do you mean ejaculates?

You got your period. It means you aren't pregnant.

It means that you need to work on and improve your written English and perhaps not use slang words.

It really means nothing, since having sexual contact does not cause a period, pregnancy does stop them, so it will mean you are not pregnant, nothing else.

One thing is there is something wrong with your period. You should take it seriously.