A nice puzzling Story

Once two men sat in a bar drinking. The first one said to the other ,"I have a hell lot of family problems." The second one said ,"I'll tell you mine. I married a widow having a young daughter. my father married my daughter and so my father became my son-in-law and I became my father's father-in-law. My daughter is my mother and my wife my grandmother. More problems occured when I had a son. My son is my father's brother and so he my uncle. Situations turned worse when my father had a son. Now my father's son i.e. my brother is my grandson. Ultimately, I have become my own grand father and I am my own grandson. And you say you have family problems".