What should you do? You should talk with your husband and try to find an agreement you both can accept, that isn't draining to your both, and that satisfies you both just enough for both of you to have happiness.
Marriage is commitment to work together even in the roughest of times, and even when you disagree on an important topic. You should do your best to work with your husband to find both the give and the take that is necessary. I generally call this "the middle ground." It's where you find where you both can meet in the middle without too much stress on either end but just enough happiness in the center. It isn't necessarily easy finding the middle ground, but it isn't impossible even in the hardest of situations. Sometimes finding that middle ground means you have to have many, many conversations together and really take time to work together and through whatever problem you're facing.
Please realize that you don't need a caregiver to attend to your regression to be able to regress or enjoy your regression. I'd suggest you initially take the time to try to find ways to make your regression most fulfilling for you without an additional person on standby to play a part that is honestly unnecessary. If you're able to find fulfilling moments by yourself then the addition of another person's involvement can still be enjoyable but there is less focus on what you may imagine is magical.
In reality, parents are not as frequently involved in their child's play activities as a regressor may want to believe. When a parent takes their child to the park then the parent rarely plays on the playground with the child. When a parent buys a toy for their child they rarely play with the toy with their child. When a parent turns on a children's film for their child they often multitask or even outright leave the room to tend to other tasks. Caregivers are like parents in a way to littles... http://www.littlespaceonline.com/app.php/personality
What I am trying to say is that there are situations that can be extremely fulfilling for you that honestly require no additional presence if you view them similarly to that of a parent/child relationship.
Your partner may already be your caregiver in many ways. It's even likely. If you partner has made meals for you, drives the car while you are passenger, carries in the groceries, comforts you with a hug when you are sad, or gives you advice then these are all things that a caregiver would likely be doing for their little partner. It might help you to write down the things your husband does for you. If you alter your perspective just slightly then I'm sure you will be able to see ways your partner absolutely provides care to you, and if you are able to see those smaller points then perhaps you can find some fulfillment in those things that can make you feel more whole in your marriage.
Your partner does not necessarily need to take on the "caregiver" label or terminology to actually be a caregiver to you. A lot of caring about and for someone is passive, and a lot of that is very natural to the point that is difficult to pinpoint what is going above and beyond typical care of a partner.
You need to really, truly figure out what specifically you're asking of your husband so that you have a better understanding of your own specific expectations. I encourage you to read this particular post with some specific advice and steps you should take when discussing this further with your husband... viewtopic.php?p=50834#p50834
If you feel that your partner doesn't care about you then I would absolutely suggest more communication between the two of you. Couples counseling may help you in that if you're unsure of how to get the ball rolling with expressing how you feel or gaining their undivided attention. Be aware though that if you have complaints then they also may have complaints, and you should prepare yourself to continue working with your partner. It is not a me, me, me situation.
Keep in mind that you don't necessarily need to use "little" and "caregiver" labels to actively be in these roles or take on these identities. Sometimes people focus too much on labels and pet names that they forget that the community is so much deeper than titles. Just because your husband doesn't want to say you're very childlike doesn't mean he doesn't actually love that part of your personality. Because, ultimately, you are who you've always been and the chances are he loves it about you but applying a "little" label to it feels daunting or uncomfortable to him. That doesn't mean it's bad, he's bad, or that you aren't compatible. Sometimes it just means that words get in the way.