question for birthfathers when you 1st found out

OK so I have a question to all birthfathers of "one night" (or so) stands. When you 1st found out the women you slept with was pregnant and wanting to put the child up for adoption did you think about trying to get custody of the child? or did you willingly go along with it? I had a two night stand with the repairman and I can't remember his name or what he looks like and we never even talked about where he lived. Though I think I remember him saying he has a daughter and he was in a relationship with a girlfriend (not the mother of his daughter). Also I think he may attend the Church that owns my house. I am only about 6weeks pregnant but the agency that I am with (adoptions from the heart) suggested we go to my landlord and see if he kept a record of who he hired and when. Which is where my worry that he'll come into the picture and take the baby and raise it and I will never get to see him or her again. At lest if I chose adoption I can pick open adoption and be updated and hopefully visit and allow the child to know my own children also. I can't tell if I am over thinking this or not but it is one of those things keeping me awake at night. I just want the best for this child.