Great wisdom in this thread although maybe I'm a bit more stubborn. I wouldn't do it. I'm 35, no kids here and every time the subject comes up from my wife, I very matter-of-factly point out that we discussed this before we ever got married and she knew (supposedly) what she was getting into. You have to put your foot down - hard - if you want to get the message across on this one. I've always viewed kids as the death of me and MY life, which I have built for myself at great personal toil and expense. I'd hate to see a "mistake" ruin all that since I'd simply resent the kid for it, which isn't really fair to them or to me. . . She always "gets it" when I put it in those terms and the subject lies dormant again for several more months.
Point is - it's YOUR life. You owe nothing to a child you don't have. Decide what's important to YOU and nobody else. Don't let anyone bully you (or guilt you) into sacrificing what you want out of life. This ain't no dress rehearsal and you only get one go-around. If you don't want another child I really think you've got to grow a backbone, stand up to your wife and tell her firmly (but kindly and gently) in no uncertain terms that it isn't going to happen - it simply wouldn't be fair to you. In this manner you turn it around on her, so that SHE is the one faced with the choice to make - be unfair to you or "selfish" with her own desires. Dirty tactic perhaps, but being on the giving side of a guilt trip is better than being on the receiving end of a guilt trip as I look at it.
If she really makes an issue of this, quietly prepare your finances for a divorce fight. I think Moses' words are wise. I'm very fortunate in that my wife and I did discuss it before we got married and that she knows it and wouldn't be so unfair as to place her "change of mind" before what we'd already decided and that I'm clearly against. I hope you can get into the same situation. Good luck.
Or just go get the "big V", don't tell your wife, enjoy lots and lots of supposedly "procreational" sex and when she doesn't get pregnant just shrug and say "I dunno what's wrong". Evil, I know. . . >
