if i loved them i would let it....
if they loved me, they probably wouldn't let it happen
if the situation was reversed i wouldn't sleep with someone i loved knowing i would have to take them through what i was going through, especially if we had children together...
again that's another point. if i wanted children and i was happy to deal wit the consequences of raising a hiv positive child while probably becoming hiv myself, i think it would be a matter of how strong the loved bond was between myself and the mother and how much we as a group wanted to have children.