Thank you for asking this I've been wondering the same although sometimes I'm a lil I guess soar I have not bleed or been in bad pain but I have been worried thanks again for ur question :)
as long as your not bleeding you should be fine. just beware that during early pregnancy your cervix is "irritable" so if you have rough sex it can cause some spotting....it's okay to spot so try not to worry. Talk to your ob next time you have an appointment, there is no reason you guys can't have the same sex life before you got pregnant. Enjoy it now because it gets harder the farther along you are.
Although when you get to your second trimester laying on your back is a no no. it can block the blood flow to your baby and yourself.
sex is actually good for the baby, and as long as it doesn't hurt and feels good to you then there should be no worries.