I think it is generous - even if I can't agree with this sort of thing in "real life". But I also think Nicole must think of herself. Knowing what is means to carry a child and bring one out into the world, I couldn't do it for another person, especially if I hadn't yet had my own family and was starting a new relationship. I think Nicole feels extremely obliged...perhaps even guilty for missing so much time with Maya as they were growing up, and this is no reason to carry another person's baby.