We can choose because it is happening within our bodies. It would not be right or fair to let a man determine what happened to my body against my will. Whether he wants the baby or not- it's her body and her decision.
Is it fair for a woman to have a baby unwanted by the man? Yes. Again, because it is her body. His desires do not trump her bodily autonomy, ever.
Men need to take control of their reproduction and use all available contraception. If she says she's on the pill there's nothing to stop them wearing condoms. A PP mentioned a latex allergy excuse- nope- latex free are widely available. If he never wants kids, get a vasectomy.
My view is- all hetero vaginal sex risks pregnancy. All of it. Pregnancy is a possibility every single time. We all knw this and all take this risk knowing what the consequences could be. If you can't deal with the possibility, don't have sex.