I think it's probably true that some of it comes down to luck. I had never even conceived of the idea of being a mommy until I met an amazing guy who also happened to love having his diaper changed! Unfortunately, we are no longer together . But we did have a "normal" relationship as well as our "private" relationship of mommy and baby. I find that now we are apart, it extremely difficult for me not to have a "baby". It brought a new level of intimacy into our relationship and at this point I find myself searching for that again.
In his case - because I was not an AB/DL - it was pure luck he found someone that not only participated in his lifestyle but came to enjoy it as much as he did. In some ways, I think it was nice because both of us had little expectation of what it "is" (he had never had a "mommy" and I had never been part of the lifestyle) and we just made our own patterns as we went along.
One thing I will tell you is to just be honest about your needs and desires. He was very honest with me, yet at the same time drew the line between what he NEEDED and what he DESIRED. Lucky for him, his desires were fine for me, but he NEVER made me feel that I ABSOLUTELY had to participate AT ALL. In fact, when he told me about it he actually stated that all he really NEEDED was for me to know about it and accept it - even if I didn't participate at all.
This gave me the chance to think about it and consider my own boundaries (which there are apparently few) and let me come to the decision on my own that I was -in fact - a "mommy". Pure luck on his part.
I credit him with discovering another part of myself I didn't know existed. I didn't become his mommy simply to "appease" him or to stay with him because I loved him. It was more like he turned on a light for me.
I guess what I'm trying to say is that you should just go out there and meet people! Don't tell just ANY girl that you love being diapered, but know that when you tell the RIGHT girl, it can happen! She just may love being your mommy as much as you love being diapered!