Wife is leaning towards castration for me.

Maybe you can find a burdizzo and use that yourself?
(It's NOT a good idea, but is possible.)
You can also either purchase estrogen or spirotone or androcur. Androcur can be rough on the liver, and is not available in the US; Spirotone is a potassium-sparing diuretic used for red pressure control which also reduce testosterone; and Estrogen will also cause feminization. You should have regular doctor's visits for this whole thing, and it's not cheap. Spirotone is not permanent, androcur might be, not sure; estrogen may not end your testosterone, though it should reduce it significantly.
Also, there is a sort of "partial" sex-change, where the doctor only removes the "extra" and leaves you smooth below. Pee like a girl the rest of your life, but no neovagina.

What are your hopes? Do you want to be more sissy? Attract men? Learn to cum while soft, form penetration? Just have nothing down below? What sort of financial options can you swing? (You don't need to tell us, just think it through yourself.) Would chemical castration do (Spiro is comparatively cheap)? You can also inject things into the testicles which will cause tissue atrophy or damage, necessitating operations to remove them. Lots of options, but you'll need to do the legwork for what and how to proceed.

The term castration is over-used. Think more specific. Do you want to be sterile but have your penis and balls, have your penis removed (penectomy), your balls removed or both your penis and balls removed. **I** would favor the penectomy. Oversimplification coming - the balls produce the stuff that keeps you horney. That makes your need which keeps you in line. Remove those and you basically loose that turned on feeling.

FantMstr,
It IS possible to move the testicles inside the body, mounting them similar to ovaries.
That would give the "Smooth Sack" look, keep the horniness, and with a penectomy, you could make the whole thing sort of work out, even to learning to cum from penetration.
A truly devious surgeon might even be able to move the head next to the prostate, to add to the learning curve... And the ejaculate would dribble out, of course, leaving a nice wet spot in sissy's or cuck's panties... She WOULD be wearing panties, of course...

Now for those who want to NOT allow any sexual relief... Full on penectomy, of course, keeping everything else. I'd suggest the internal positioning of the balls, though, to keep the drive as high as possible.

I've fantasized for years about a full package removal. Including a urethral transpositioning to the perineum. Just leaves a small hole for urination. I 1st saw the photos attached about 15 years ago and nearly came hands-free just looking at them.

Odd to think of losing your sex making me horney. But it does.
George Nobush
Follow me on Tumblr.com: http://georgenobush.tumblr.com/

Castration is an answer for being oversexed. I was once always wanting it. With my wife and in MFM with my wife and another man. We worked around to presentation and the ultimate presentation of them having me castrated. Long story made short, yes it does work. I am a eunuch with little to no interest in sex and now one of our male lovers is really more her husband. I haven't had sex with a woman and no interest. Even sucking his cock is more for offense as is being whipped. Once your balls are taken out, you really have no interest in sex and no desire at all for the pleasures of a woman. To her, you become completely useless a couple weeks after they are taken out. Most of us become completely impotent and no hard on at all within a couple weeks to a month. To many not even watching is of any interest nor is gay interests such as sucking his cock, offense and being beaten or whipped as others watch becomes more your thing than sex.