What's really going to screw you up is this:

Down the road you meet a wonderful woman. How are you going to explain that you are paying child support for a child that isn't even yours? How's she going to feel about your X? There's going to be bad blood there. All I'm saying is that your feelings are going to change in the future.

I think you are going to regret this. Please challenge it.

You could be sending the child to college as well. You could be going in on a wedding. Think twice please.