Sorry nadsss, cross posted.
If your first baby is rhesus neg, then it may not be a problem second time round - it's the pregnancies that follow a rhesus positive baby, as I understand it (I'd check this with your midwife), though in rare cases it can be an issue with the first rhesus pos pregnancy.
But I think, any pregnancy counts when working out if its the first or second , not just ones resulting in live births - so if you had a miscarriage first then that counts. And you wouldn't necessarily know whether that baby would have been positive or negative. Does that make sense?
In the case of a first baby, although it's unlikely to be an issue if you don't have the anti-D in terms of the health of that first baby, it will have an impact on subsequent pregnances if the baby is rhesus positive. Also, there are things called sensitising events that can happen during pregnancy that may have an impact - if you have a fall for instance, then you'll be given anti-D.
I wouldn't refuse it in a first pregnancy if your partner is rhesus positive. In fact, personally, I wouldn't ever refuse it if my partner was rhesus positive.