Slight correction. The law does not say the OP has any legal responsibility to support this child and her child. The law says that the OP's HUSBAND has a legal responsibility to support his child. Therefore, the OP can do whatever she chooses regarding the situation. The problem belongs to her husband.
If you wanted babies all to yourself, you should have created them by yourself. Until you do that, children have the right to BOTH parents, especially since you found them suitable to procreate with.