A lot of us have been in your shoes and I can tell you right off that you need to figure out what you want from chastity. I think for nearly all of us males Chastity starts with the desire of really kinky sex with our partners. We introduce it to them and things don't progress the way we want and we get discouraged and upset about it. However one key thing we often forget is that many of us promised our partners that chastity is going to be all about their pleasure. The most common mistake we men make is that we make chastity more about than we do our partner.
The other side that you need to watch out for is being pushy, there is nothing that's more of a turn off than a submissive trying to tell the domme what to do to them, also called topping from the bottom.
I started out the same way, thinking I was trading in masturbation for kinky sex and a 24/7 mistress. I kept thinking that any day now she was going to come out of her shell and be the mistress of my fantasies... I was dead wrong and the more I pushed and the more books I bought her were doing nothing but making me more frustrated.
Then I finally had an epiphany, I was trying to get her to do everything I wanted instead of what she wanted. In fact I don't think I ever even asked her what she wanted. She really likes Chastity but not all of the associated kink. Once I finally made it about her and stopped worrying that she doesn't really want to use a strap on on me among other things out D/s dynamic grew just a little. The more I submit the more confidence she feels in herself and appreciates that I am making this relationship about her. I would describe us as a vanilla couple with a little kink on the side.
As for you, 3 months is a drop in the bucket when starting this type of relationship. We've all read the crazy stories about how some couples just immerse themselves into the lifestyle but believe me it's not as common as you think. The grass always looks greener but a lot of times other factors are at play when you read others couples blogs and how kinky and crazy they get. In sones cases they are already into the kinky shit and just happened to add a chastity device to their play. My Ms and I are 3 years in and like you I thought we'd be much further a long at this point. But that begs the question of from who's point of view are you further along, from yours or hers?
If you really want this lifestyle to become anything close to what you hoped then you need to truly make it all about her. Sure you can ask for things or make suggestions but don't pester and whine when she doesn't want to do what you want to do. The best advice o ever received in regards to encouraging your domme to grow is PATIENCE!!!! I can't emphasize that enough and even when I thought I understood that I still was screwing up big time.
Save yourself a lot of angst and frustration, stop worrying about the kinky stuff andvwhst you want, make your wife feel like the queen she is and let the rest fall into place. Things may never progress far beyond vanilla that's just how some people are. If you enjoy what you have right now then you should encourage it with your obedience and let things happen for her by her seeing changes in you. Trust me not one of us is perfect and other people are incredibly lucky with what their keyholders do but the majority of us start out just like you.