Unless you know this man extremely well, you shouldn't assume that he's not totally against the idea of a pregnancy. This is something that you should have discussed with him before having sex. If he said he doesn't want to have a child, then he should be using condoms. If you aren't currently using any birth control, this is something you should be up front with him. Not to sound preachy, unless both of you have been tested for STDs before you engaged in sex, he should at least be using a condom.