You should read Nick's newer blog post about women sabotaging themselves. It could be that this woman is afraid of falling in love with you. She might be afraid that you will eventually leave her. So she can't put the energy in to the relationship.
You should try to explain her behavior to her, if it's a real barrier to your relationship. Is it also that it's just hard for a mother to find a sitter for date night?
If I was dating someone, and they did not put as much energy in the relationship as me, then at some point I would find someone who would.