My girlfriend is the same way, she is actually the icebreaker / instigator in getting me in little space, I normally tend to stay on the dl side of things, but sometimes she just melts me in little space, even if its only for a short time.
For instance yesterday I was working in the yard and I came in for some water, while in the kitchen drinking she came in and gave me a playful butt pat, after the pat, she smiled and said I needed a change, to which she lead me hand in hand to our bedroom were I started undoing my jeans top button, she gently hit my hand and said she would do it all, after my jeans were undone I plopped down on the bed and she took my pacifier out of the draw and put it in my mouth. The rest of the change was uneventful but for that brief moment in time I was little and letting mommy do her thing.
After the change she put my jeans back on, gave me my wet diaper to put in the garbage can and sent me off to finish my project. It perfectly normal and I love those little times during the day, it makes me feel so well rounded.
My favorite event this year was the whiskey festival we went to, I knew she packed a diaper bag and some onesies figuring that it was going to be my nightwear, but was shocked after I got out of the shower at the bread and breakfast we were staying at to see a plain white diaper and a navy blue onesie sitting on the bed, she had that evil grin look and said under no circumstances was she willing to take a gamble at a whiskey event and me keeping my pants dry or trying to find a bathroom (of which there were hundreds of portajohns all over the event) never the less we had a fun weekend.