However you have arrived at asking this question, the circumstances are difficult and would leave anybody wondering what to do and whether they could ever win. Nobody wants to battle for children that they care about, but there is some help at hand.
It is absolutely possible for non-biological parents to win custody; however, to be successful in a case like this, you would need a family attorney to assist you and put forward a case. So the first port of call would be to meet a selection of specialist family attorneys and select one that you feel would present the case the best. Tell them as best you can all of the facts and they will advise on what can be done.
Will a Biological Parent Always Win Custody?
In most cases, a court will rule in favor of a child staying with a biological parent wherever possible. This means that if you are married to a person that has children with someone else and that other person is capable of taking care of the child, then the child will go back to a biological parent. Visitation rights or custody of children to non-biological parents must be approved by the biological parents if they are able to or are suitable to approve the decision.
There are some obvious unfortunate circumstances where a non-biological parent would be favorable for custody. These would be in situations where a biological parent is deemed unfit, or it would not be in the child's best interest to remain in their care. Of course, if a biological parent or parents are absent by desertion or have passed away, a non-biological parent would be considered for custody in these scenarios too.
Doing What's Best for the Child
There are some caveats to this though. With every single situation, the very center of the case will be built upon what is best for the child. If a non-biological parent hasn't spent considerable time with the child or isn't considered as family by the child, then the court will need to consider if a non-biological parent in the best interests of the child.
Whatever happens, remember that the courts will always be ruling in favor of what they think is in the best interests of a child, which is the same thing that you are trying to achieve too. Speak to a family attorney and describe the situation, and they will be able to advise what can be done and what the likelihood is of custody being awarded to a non-biological parent.
For more resources, visit a site such as http://www.cappolellalaw.com.