My Heart Belongs to Daddy (1982)

An incarcerated father gets freed and finally gets the chance to meet his son and daughter by chosen circumstance, both of them not recognizing him. He continues his presence around them pretending to be somebody else just to reclaim lost time, all the while around the presence of his wife who's already about to get remarried, working around an unspoken agreement to continue pretending that their dad (him) is already dead.