As a dominant, you actually have it easy. If you were submissive and married to a totally vanilla woman, you'd likely be SOL.

The trick is to move slowly. You want to gradually take a more and more active role in leading your wife. You need to be the one who makes decisions. For example: don't ask her where you're going out to dinner, tell her "Let's go to Carlito's tonight." If she says she wants something different, reply with something like, "I'm really in the mood for Carlito's, can we do that another night?" Then, when she does something that pleases you in the next week or so, tell her your taking her to the restaurant she wanted as a "Thank you." After a few iterations of this, "as a thank you" turns into "as a reward."

It largely comes down to taking control. Just put yourself in the driver's seat, and unless your wife has some strong dominant tendencies, she'll both love the new you and start deferring to you.

As far as bedroom activities go, it's largely the same. Take charge more. Start by simply being more agressive. Grab a handful of hair and hold it (close to the roots! at the end just hurts for no reason) while you're kissing her. Pick her up and change her position. Slap her ass a couple times while you do it. If she asks, just tell her you've been reading and thought you'd try some things. She won't object, but might wonder at the change.

Above all, make only one change or introduce one new thing at a time, and do that thing until she's used to it. Introduce a new position, then do it a few more times until that position becomes "normal." Then add something else in, like more dominant dirty talk. I have yet to experience a woman who won't, in the middle of sex, give you whatever answer you want to any question you want. Start with "are you a naughty girl?" I guarantee she'll say yes, so long as you're actually doing your part in bed. Eventually, "a naughty girl" turns into "my slave girl." After that, add a blindfold. Small, incremental changes, done with care, have wide-reaching reactions.

Throughout all of this, accept that your wife will have some hard limits. She's not a character in a story, as much as you might want her to be. There will be lots of things she won't do, and admitting to being in any type of BDSM relationship may very well be one of them. She'll love being tied to your headboard with a necktie and giving you head blindfolded while calling you Sir or Master, but she's not into bondage. She'll do the housework and give you a massage while calling you Sir "to set an example to the kids" but she won't call herself a slave except when you're fucking her.

So you need to figure out what's important to you. If going to munches and parading a girl around on a leash are important to you, you may be disappointed with your wife. If, however, you want her to act the way you tell her to act, defer to you as her master, treat you with respect, and be devoted to you, that is likely well within your reach, and 90% of getting it is adopting the attitude, without ever saying it, that you're the man in the family, and you're in charge. She can ask for things, but getting them will be contingent on your approval and her good behavior. The only way you'll get there, though, is with small, incremental changes.