I would love to give you suggestions and opinions to make things better but it would be coming from someone who has no training in this matter and would most likely make things worse. Form your post you both were young when you got married and 16 years is a huge investment in each other and in addition to that, you have an impressionable age child.
What I can tell you is, I believe having a good therapist can help you work through this. I never believed in therapy UNTIL I went to one and they helped me remove a huge burden I was carrying which allowed me to proceed to a good place. They didn't tell me what to do but guided me to make my own decisions and I've been forever grateful.
I've been reading post on this website for several years before I joined and found I'm not as unique as I thought and neither are you or your situation. I wish the best for you.
