So you're saying it's ok for one parent to make a unilateral decision about how much the other parent has contact with their child as long as they think (and you agree) that it's best for the child?
Because I don't. In all circumstances, regardless of the sex of the parent, an agreement between the parties should be reached together and if there is no agreement, or there are mitigating circumstances such as abuse, then an impartial third party should be used to ensure that the child's best interest are at the fore.
It's not right when women do it and it's not right if a man does it either.
In this case the step-parent has illegally represented themselves as the biological parent and regardless of how "fair" it is, this should be rectified to be in line with the law. If the step-father, in this case, had wanted actual legal parental responsibility then they should have adopted the child, he chose different. You cannot gain legal rights through illegal means.
Furthermore, if he had wanted to remain a significant adult in the child's life, regardless of legal status, then alienating the mother from the get go and making her afraid of losing her child is probably not a great opening bid.
The OP has done nothing worse than accepting help with child care from people who were willing, able and in full possession of all the facts. She did not take a year out to pursue her love of crack cocaine, or "find herself" in India or any other self indulgent pursuit. She took a year to establish a sound financial future for her child by leaving him in a secure and established home, without all the toing and froing that shared daily care would have entailed and whether you or I, or anybody else would have made the same decision is by the by, it is hardly grounds to treat her as an evil neglectful mother who deserves to lose custody of her child.