Blood type compatibility in pregnancies is important. The healthier your kids without medical assistance, the better. In a nutshell, your fetus is going to give you no issues if his/her blood could be donated to you in the case of a transfusion.
Since we inherit our antigens from both parents and an antigen incompatible with the mother's has to come from the father, a father whose blood type allows his blood to be donated to the mother is the perfect partner.
If you are female:
Search for a male who has a blood type that would enable him to donate blood to you.
If you are a male:
Search for a female who could be a recipient of your blood in case of a transfusion.