A friend of ours lost contact with his 3 year old son when his ex wife told downright lies in the divorce court, and said the little lad was actually her lover's son. She soon married that lover. All contact was refused then, by the court. Our friend was too devastated to handle it, and legally he could do little, so he remained out of contact for years, until the son grew to adulthood, and got engaged.
While seeking out his birth certificate the son discovered what his real name was, and who his real father was. Meanwhile his mother, our friend's ex wife, decided she didn't like her DIL-to-be (a lovely woman who turned out to be a great Mum), and cut off contact. The lad sought out his father and our friend got this wonderful and unexpected phone call "Are you Mr .......? I think you may be my father".
Our friend now has regular contact with his son and family, and was there for the arrival of his three grandchildren. They live about an hour and a half's drive away, so he sees them all at least once a month. The lad is clearly our friend's real son - they look alike.
I know this is little consolation for the present problems, but sometimes they do work out in the end.