<human>: Can you condense the text into three sentences or less?

My wife and I have been together/married for 3 years and I've only known my stepson for 2 years. I never really wanted kids (my wife knew this) but because he was an older child and was (and still is) a good kid, things were fine and we got along well. 

Recently (within the last week or so) he's started calling me 'dad.' For some people this would be great and feel like the ultimate level of acceptance, but it makes me really uncomfortable. I feel bad that I feel this way because I know his dad isn't around and every kid needs a dad, but taking on that full role and all of the responsibilities of it isn't something I was looking to take on when I got married and my wife knew this. I would also feel really bad having the position of his dad while not feeling the love for him that  I imagine a father is supposed to have for his child, but I don't know how to approach this subject at all and my wife is no help.  She feels like this is the greatest thing ever and when I told her how I felt about it, we got into a pretty big argument over it and she feels like I'm wrong. 

So ultimately, I guess my questions are an I wrong and what can I do?
<bot>: I don't want my stepson to call me 'dad' but I don't know how to get him to stop.