My wife is pregnant with our 3rd we have been discussing getting myself a vasectomy my friend...?

My wife and i have two sons one is a year old and the other is two years old well she is pregnant with our 3rd and we think were done and we have been discussing getting myself a vasectomy since it would be easier on me then it would be on her. Well i am fine with that three kids is more then enough and i love them more then anything as well as my wife! Well i was talking to my friend who is a girl and she doesn't think i should do it cause she thinks it would be robbing me of my manhood and that she thinks if we don't want any kids then my wife can just as easily do it or get on BC. I told my wife what she said and she practically blew up in my face =/. I was so confident about it and now i am not and i am unsure what to do! It isn't like i was talking about anything big with her or about my wife not sure why she got upset. But i know i need to distance myself from my friend cause she told me she was inlove with me! Advice?