RD, rather than spoil her try to be the same loving, consistent father you've, presumably, always been with her. Spoiling children at a time like this is never a good idea. Above all, they need to feel that both parents still love them, and that isn't about to change because their parents are no longer together.
The co-parenting sounds like a good idea, and it's important that you and your STBX present a loving united front towards your daughter, no matter what your differences with one another. You're divorcing one another, not your child, and she needs to know that although you're no longer together, you are both together as far as her interests are concerned.
The co-parenting sounds like a good idea, and it's important that you and your STBX present a loving united front towards your daughter, no matter what your differences with one another. You're divorcing one another, not your child, and she needs to know that although you're no longer together, you are both together as far as her interests are concerned.