Getting Pregnant After Vasectomy
Though the chances of getting pregnant if your partner has a vasectomy are low, it's not unheard of for some of the bits to grow back together, allowing for sperm passage and pregnancy.
This, of course, is not the norm (else our guys wouldn't be going through the procedure, lol!) so when trying to conceive, the best route would be for your partner to have a vasectomy removal. That is, unless you have sperm stored or are willing to use donor sperm.