Pro: It's her finger
And she'll be wearing the ring for the rest of her life. Going shopping together ensures that she'll get the ring she wants; not, by analogy, a fantasy football team with 10 kickers and 1 running back.
Con: It's as Romantic as a root canal
There goes the surprise. There goes tradition. There goes the fairytale story. (Then again...do you really give a damn about fairytales?) If you've already spoken about the engagement—and she's already talked to you about her ring—you obviously have less to lose.
pro: She will feel empowered
From a progressive/feminist perspective, she'll feel like a partner in this, not just the doting wife who will take whatever she's given. (Note: we are not suggesting that the traditional surprise-ring is misogynistic—it's just another interpretation.) Again, remember, this is a bigger deal than her wedding dress, cake, or wedding venue. Regardless of what she might tell you, she'll appreciate a say in the matter. (Think of it like Valentine's Day—some girls might pretend that they hate Valentine's Day and despise the Hallmark cheesiness...but no matter what they say officially, they always like roses. Not that we would ever stereotype...)
Con: It Adds to the money stress
Having the bride-to-be there adds stress and gives the merchant an extra hand to play. "Don't you want your lady here to have the biggest diamond in the world?" Cut to soon-to-be-wife giving you puppy dog eyes and you'll soon be spending outside your budget.
Pro: "window Shopping" allows you to avoid (some) pressure
To address the "money-stress" you can split the difference and make a compromise: you won't buy a ring together, but you can do some window shopping to get a feel for her preferences. Agree that no matter what happens—no matter how perfect the ring—you won't pull the trigger. This way you can get her input without feeling on-the-spot pressure.
Con: It's Not traditional
Eh. It's not exactly traditional for you to have sex before marriage, but you do that, right? Spontaneity and romance are both valid reasons to skip the couples ring shopping, but "tradition" and "protocol" make less sense.
Pro: It will reduce your stress
And that's what really counts, right? If you've already discussed getting married—and she's just waiting for you to pull the trigger—this gives you optimal peace of mind (if minimal surprise-factor.)
Con: It's not irreversible
Unless the merchant is shady—in which case, don't buy from him—you can get a return policy that will let you change or return the ring. Even if you screw the pooch and get the wrong size, the wrong setting, and the wrong kind of stone...you should be able to make the necessary changes and come out whole. The ring is something you can undue. Popping the question itself, of course, is a different story...
This is the #1 complaint we hear from women: that their fiances say they don't care, but then, after months of gloomy silence, they criticize at the last second without offering anything constructive. It's a fair complaint. To keep good Groom Karma, every once in a while you must offer some positive suggestions, take a stand, and, if Our take? If the proposal is going to be a surprise—even if you've discussed getting married in the abstract—go with an educated guess (click here for how to find her style and size) and buy your own ring. If, on the other hand, yours is the type of relationship where you have already negotiated the time and place for the actual proposal, well, I guess it's never too early to start letting her make all the major decisions anyway...
SEE ALSO: while ring shopping, here's our take on Online v. in-store shopping.