I really don’t think it’s possible to say what you ought to do.
Conveniently, we seem to be made so as to rationalize the outcome of most turning-point decisions as ultimately being the best thing, all things considered. (Reducing cognitive dissonance.) So, as you said, it’s very rare that someone would regret having a child… even single mothers who consign themselves decades of poverty will typically say, “I wouldn’t give up my baby for anything, but don’t do what I did.”
Having a child definitely alters your life, and not always in ways welcome or appreciated. My daughter’s coming up on two, and her lil’ sister will be arriving in a couple of months. I have no regrets: always wanted kids. My wife wasn’t sure about kids, then thought one would be alright… then thought maybe two. She’s very happy…most of the time… but Sprout is very, very easy to care for. My sister’s daughter is now a year and a half, and is loved to bits, but she’s far more difficult to care for. Neither my sister, nor her husband, want another: not now; not without some means of sharing the burden should the second prove as trying. Luck of the draw.
I believe that, later in life, most people regret not the mistakes they made, but what they never even tried to do. That may not mean ‘have a child’; it may mean that having a child you would forfeit your freedom to do x, y, z, and you’d regret x, y, z. (Are you doing those things?) I suppose you could take a utilitarian approach and weigh (all the things you’d like to do but couldn’t with kids) x (the probability of actually doing them) against all of the (for you, unanticipated; for your wife, yearned for) joys of parenthood. Not an approach I recommend, because it involves tossing incomparable goods onto the same set of scales, but an option all the same.
Having a child, what would you give up?
Financial security? Kids are definitely an added responsibility. But, IMVHO, you’re exaggerating the horrors of a state school, and of a smallish apartment. I’d kill to have a mortgage, particularly on a cozy little place: instead I have the equivalent of a small mortgage on my brain, and little prospect of escaping rent anytime time in the foreseeable future.
The freedom to know that you can do as you please when you get home? Yeah, it’s a loss. I lost the ability to sit down, waste time on f.com, play Civ, go play hockey two or three times a week, etc, etc. I gained a lil’ munchkin who races to open the door when she hears the keys in the lock and always greets me with a shout of “Baba!” and big hug, who (at this point) wants nothing more than to play, read, draw pictures and drag me around by the hand. I am happy; it is a tradeoff. No regrets, so far. But, what would you really be giving up, beyond knowing that you could do whatever you fancy? (btw, I hope you don’t feel obliged to answer. I think these are good questions, but the answers and their relative weight are entirely your business, and may take a good deal of time to work out.)
You don’t want kids to take up too much of your day, because you’re already teaching kids half the day: ok… change your work. There are options out there; it’s not a difficult adjustment.
Worried about how the kids might mess up. Kids will mess up: comes with being people. Don’t worry about it. Teach 'em right from wrong, give 'em plenty of chances to practice making the right choice, then let 'em find their own way.
Do you want to mow through the best and worst case scenarios?
You have a kid and love your life.
You have a kid and hate your life.
You have a kid, hate your life, and leave your wife. (What would she think of that deal?)
You don’t have a kid and love your life.
You don’t have a kid and hate your life.
You don’t have a kid and your wife leaves you to do so. (What would you think of that deal?)
I think this may sound too much like encouragement to have a kid; that’s not my intention. Some people really shouldn’t have kids. My impression from the little you’ve written is that your arguments against having a child are largely emotional, based on fear and selfishness. Put that way, your reasoning sounds rather ignoble, but what of it?: A motive doesn’t have to be pure or rational to be compelling. (Still, I don’t know how much weight I’d give such reasoning. Nonetheless, it’s probably a bad idea to let yourself be ‘guilted into’ parenthood.)
Maybe this is a useful question: who (or what) are you? You say you need to be true to yourself. Very well, what are you being true to? What do you value/admire/require? Is enacting those virtues important to you, or are you content to think well of an idea without putting it into practice? Are you (or your values) fixed, or malleable/evolving?
I don’t envy you your dilemma. It must be very difficult to decide how to decide, as well as what. As your wife is 30 you have some time, but maybe not a lot if she’s determined to have kids, with or without you.
I wish you wisdom and luck.