NTA. & this story is similar to mine.

My biological mother was never around while growing up. She divorced my father when I was 6 and left me with him. I had a tough childhood but my father gave me everything he could. He remarried an absolute angel who is now my stepmother. She truly loved me and cared for me like her own, but I grew up always wondering about my biological mom. When I turned 18, she reached out to me again and we reconnected. While yes, I was an 18 year old adult, being reconnected with my biological mom turned me into the child that grew up without a "real" mom. I was just so hypnotized by her, and all my old emotions that I had as a child came surging back. I started acting distant with my stepmom, and I said some pretty terrible things to her such as, "You're not even my real mom. I don't want to live with you anymore." It broke her heart. I never saw anybody cry so hard and sincerely like that, but I didn't care at the time-- after all, I had my "real" mom!

It wasn't until several weeks later that I saw why my biological mom wasn't in my life. She was manipulative, selfish, and an all-around terrible person. I instantly felt terrible, and to be honest, I still cringe and want to crawl into a hole whenever I think about how immature and rude I was to my stepmom. Long story short- my stepmom is still in my life, and is the only person I consider my real mom.

While our stories differ a bit, my past experience with my own stepmom gives me a small idea of how you may be feeling. Your son may be going through a personal dilemma as well. While it's fine that he feels the way he feels about Chris, I am sorry that you feel so neglected and rejected as a result. I hope that he will realize one day, just like I did, that blood isn't the only thing that makes you family. Your feelings are valid, and I hope you two are able to reconcile.