Absolutely ok. Blood group does not interfere in marriage in any aspect. (The only case it matters is when the female is Rh -ve and husband is Rh +ve, the female is given a specific injection after the birth of her first child (if the child is Rh+ve) to avoid complications in the second child. It is most commonly done and without any complicatios and sideeffect. In this case too marriage is not a problem at all. )