I would also read the Wikipedia article on Infantalism so that you can understand what you're talking about. I think finding acceptance centers around communication. If you have a better understanding as to what this is, you can better convince him to accept who you are.
I had to tell my wife when she discovered my diaper order, so I went on several sites to gather information, and one of those sites was this one. I got a lot of help from other members, all who urged me to be open and honest. My wife was very accepting, probably because we love and support each other.
In church weddings, the passage from 1st Corinthians is often read, and it reads like this. "Love conquers all things, so keep love first". Love is recognizing that none of us are perfect, but because we love, we live with each others' imperfections, and those imperfections don't matter, as long as they aren't destructive. There is nothing destructive about wearing and enjoying diapers, or regressing and feeling "little". Our introduction thread says that diapers don't rule our lives, and that's important to remember. There is a time and place for all things, a time to wear diapers and a time to be a grown up.
That's important in how we express our love to our partner. Maybe some diaper play enters into it, and maybe it doesn't if our partner is uncomfortable with it. But even if he is uncomfortable with your diaper wearing, he should accept that this is who you are, that you will need to express the desire to have some "little time" when it works for the two of you. I hope this helps.