Been married for 38 years we both decided we didn't want kids.  My husband told me he had a daughter and paid maintenance when we first met, he also told me he did not want her as part of his life.

out of the blue his daughter got in touch saying she had been looking for him for 20 years.

suddenly she is in our lives and my husband is obsessed.  I feel a huge resentment as he never gave me an inkling that this would happen.  He always said kids were a pain.