My DF's mother is in her early 40's, and she has been in a relationship with a man for 16 years. This man is married and has two children of his own. He comes over to her house after 9pm nearly every night of the week to spend time with her. My DF has been brought up to believe he is a father figure to him despite him not truly being around in his younger years - however now DF is an adult he doesn't consider him to be any kind of father to him.
My DF knows NOTHING about this man despite his inclusion in his life over a number of years. He doesn't even know his real name, where he lives, his occupation etc... although he has made some assumptions based on what he has seen. He is very careful to keep wallet/phone/documents carefully hidden or on his person.
My DF has a nephew who is 4 years old. He considers this man to be Grandad. Now, this is where my problem lies. Please tell me if I am being unreasonable by considering the following issues.
If me and DF have children together, which we are planning on, I do not want this man anywhere near any child of mine. I know nothing about him, neither does DF. He leads a double life - what is he capable of? I don't consider him to be any kind of grandparent to my future children, and simply can not see this changing, even if by some miracle he leaves the wife (ha!).
I can see this becoming a massive massive problem with DF's mum. She dotes on her grandchild, and has him overnight and looks after him regularly. I just can't see how this is going to work if I won't allow a similar close relationship.
Please discuss, and AIBU?