What if MC lived his first 2-3 years with Bella and James?
Theory
When MC went to Bella in EP4, he talked about three relationships with Bella. As far as I remember Bella was thinking about a three way relationship (Boy,Boy,Girl).
If now Lynette was in a three way relationship with James and Neil and MC was begotten in the process. Lynette dies. No one knows who the father is. Neil who always moved from building to building moves on and little MC stays with James.
James marries Bella and little MC has a loving stepmother. James has doubts whether MC is his son or Bella is bitching (take your pick). They do a paternity test and it turns out that Neil is the father. James informs Neil and Neil fetches his son.
(That nobody writes me here, that MC can remember with 2-3 years. Then I get the Aunt Jill theory out of the drawer again).
Bella and James want a child of their own a few years later. Oops, one of them is infertile. It comes to an imbalance in the marriage. Bella blames James for giving MC away.
You know the rest.