Trying to get pregnant.

I have a 13 yr old daughter with a previous relationship and my boyfriend don't have any. I would love to give him at least one child before I turn 40 and I'm now 38. So with that I don't mean to sound gross but when me and my boyfriend do it. I always make sure he does it on the days I ovulate so we have a better chance. But everytime he comes inside me it comes out. Is that normal??? I don't know if it's me or what. Please help with any advice. Thanks