Depends on the position. My ex was riding me and I stopped. She kept going and I let out something audible along the lines of "slow wait wait hold on no no ahhhhhhhh. I told you to stop." She climaxed at the same time but it was pretty amazing.
In the earlier stages of a relationship, things can get very hot. So you can lose control. Later on, it's easier to predict. But why not use other forms of non-invasive birth control like the diaphrum, copper-Tee, etc?
How fast does your partner cumm? Answer: How horny is he THIS time, and how long has it been since he last spilled a load? LOTS of variables can affect how fast it comes out.
If you don't want to get pregnant, use protection or don't spread your legs. End of story. Condoms don't feel good, and that's why guys try to convince you they will pull out. And yes, the sex is better for us too without a condom, but 10 second of pleasure is NO excuse to risk STDs and pregnancy.