You cannot make someone become a Caregiver if they are not a Caregiver; however, I believe that people within our community are naturally drawn to certain types of partners who likely display personality traits of being a regressor or a Caregiver. Your partner--likely a natural Caregiver since you've partnered well up until this point--may just need some time to process the new information as well as explore themselves and their
Caregiver personality trait. You should be exercising a great deal of patience with them right now while they discover themselves since they just haven't the same time to learn and explore as you have already.
Have you brought your partner to the online community to explore both with you as well as without you present? It may be a very helpful first step to help introduce them to other littles and other Caregivers who are active since it can help to really increase your partner's interest to try more things. Meeting other people in the community can be very rewarding and uplifting.
I would suggest that, if you haven't already, you bring your partner with you to online communities specifically targeted to Caregivers and littles. You should bring them to
resources that you believe are helpful and educational in terms of what pertains specifically to you. You could also reply to forum posts or have active conversation and ask your partner to read it over and let you know if they have any additional thoughts you might should add to something--gently prompting them to read about how you feel and what your thoughts are as well as put in some thought about their own in relation to that.
You can also make exploration fun by getting excited about joining the community together. Chat together in chat rooms, encourage him to post in fun posts, take photos together to share with community friends. Intentionally seek out other couples and talk with them with your partner about things they do, what they find fulfilling, and how they act while in deeper regressive moments together. You can also do initial partnering things like play a back-and-forth question game, where you ask your partner
Caregiver-specific questions and you show them a list of
little-specific questions to possibly ask you if they're interested in knowing.
Help your partner to see that this is a personality trait and
isn't just momentary roleplay. Help them by bringing CGL into reality for them, as a daily thing that naturally happens, and normalize it by helping them become more involved with other CGL persons.
Just because things aren't instantly working out right now doesn't mean they aren't trying or don't want to try. Your partner acknowledging that they want to take care of you alone is a huge positive sign and something you should pursue to help make work. Don't be afraid to put time and effort into your partner, even perhaps at times outright telling them what you would like to them to do or what you expect, so that they can settle in and feel confident about caring for you. Right now it might mean you need to make more effort to help them find their way, but later you will feel confident that you have a good Caregiver match for your regressive nature.