HI welcome to health care magic.........
has nothing to do with marriage, just that if one is positive (B + like you) and other is negative(like your partner O-) then there is a possibility that the child born can have ABO
or Rh incompatibility , means there may be mismatch of blood groups and the baby may loose blood and may develop jaundice
. This is preventable by going for Anti D antibodies
each time after blood transfusions or child birth. But if you do not want to take the risk at all then , you should decide. Yes there is a chance of bloodgroup mismatch i.e Rh incompatibility possible but not always 100%, and so you need to decide further