Norethindrone mini pill questions

It seems to be mixed on whether or not this is a good form of birth control. I've been on it for a few weeks and I have some questions.

Can my partner finish in me? I've heard mixed things about this across many birth controls.

It also seems mixed on how effective it is. I've seen 95% with perfect use, and 99% with perfect use. How effective is it actually?

What are the most common side effects for everyone? I've had the nausea, the headaches, the cramps, tiredness, irritability, breast tenderness, I think I've had all the ones I've read about? I'm wondering if there's more I missed?