I would suggest that you sit down and make notes of your situation. For example, Maybe a pros and cons listing of what you like about it, what is comfortable, and what is not, what is fun or exciting about it to you, what you think may make it more exciting to you. Basically a list of "Heres the thing" Maybe you can come up with lets say 10 reasonable semi normal things you like or enjoy.
Now you will need a list from her, starting with for example, what she finds OK about you being diapered, How she feels about diapering you. Is it on her terms or yours. Who decides when this playtime takes place. Is there something she may want to add to this time. Does she tease you in any way that implies, she would like to feed you by spoon or make bottles, even if it is just offering to cut up your food. etc. Are you telling her how to do this or that, are you happy with how she does things, or do you complain about little tasks such as the tapes or pins are too loose. What would make it easier for her, what kind of fun can she derive from the experience.
Basically what I am getting at is, there will be a happy medium where you both should be comfortable. When you wear. Who does the diapering, Incl the initial clean diaper from the start, then on to what about the changes, what is acceptable and what is not? cummies, wet, dirty. How you use the diaper (if at all, when she is there for example). Who else is around, are you wearing under your pants when you go to the store together, or browsing the Mall or out to a Movie or even attending a cookout at friends or neighbors or her family. See, now without asking, IDK, and maybe you do this already, and she is against it.
Learning what she thinks is acceptable, pleasing, fun or even entertaining (for her) is the best way to move forward. Learning about how she feels about her involvement in any of these things, such as what the experience in this as a play activity be like for her. Maybe it is only once a month when she "plays along", but is that instigated by you? What about the other times when "normal" playtime is initiated, is she happy with the "ol standby of vanilla activity" or is there something that she may want to try... You may find it more exciting if you give her the authority to govern when your playtime activity in diapers begins and ends the way she see's fit. Perhaps changing her title to Mistress instead of Mommy is something that can change her state of mind (Even if just a little) beginning with your very next conversation with her.
I would be curious to learn what she has learned about the subject, the difference between Ab and Just Dl, are there any things you can think of, maybe things you didn't think she would like or approve of that you haven't told her. Such as you being a lil boy, or a lil girl. Has she chatted with or even read about other couples to learn from some of their activities that she may actually like or hate, something that might make her curious and even suggest how maybe the two of you could maybe do that? Communication is so very important, but truthful honesty is the key.
