Sorry that you were never able to get to meet your birth mother and have your question answered. My guess is that she had your best interest in mind and not hers. I look forward to hearing the rest of this story for sure.
Also, the wife and I know the feeling of joy adoptive parents have in bringing home the one day old infant. Our oldest boy is adopted and we experienced that with him. I also let you know another thing, and your parents that raised you would probably agree, there was always a feeling in the back of our minds that someday the birth mother would come back and want her child back. Those feelings were pretty strong in the beginning but became less over time, it wasn't until he was eighteen that we finally let go of that fear for good. Being adoptive parents is very rewarding and very stressful as well.
Great story,
Sult