I mean vaccines aren’t always 100%. If you’ve been vaccinated you’ll have a much stronger immune response, but it is still possible to get measles if you’ve been vaccinated. 2 doses of the MMR vaccine is on average 97% effective in preventing measles infection (per Mayo Clinic https://www.mayoclinic.org/diseases-conditions/measles/expert-answers/getting-measles-after-vaccination/faq-20125397).
The bigger issue (like with Covid shots, flu shots, and everything else) is that there are elderly & immunocompromised folks who can’t get vaccines. Their immune systems aren’t strong enough to handle the small dose in the innoculation. So the only way those people are protected is through herd immunity, relying on the rest of us to protect ourselves and our community.
Aromantic and asexual are distinct, but often confused.
Aromantic/aro: an individual who feels little or no romantic attraction to others. These folks may still have relationships or hookups, but generally don’t find those evolving into long-term romantic love or monogamy.
Asexual/ace: an individual who feels little or no sexual attraction to others. These folks may still have relationships or hookups but generally don’t feel a specific drive to engage in sex or other physical intimacy with people.
Anyone on either of these spectrums can still have relationships of any type, and anyone on either of these spectrums can still be an asshole in those relationships. Aro people generally don’t form individual romantic bonds, but unless they’re also ace/asexual they are still as sexual as anyone else. As a result, it might appear that they are a bit of a player (sex without long term attachment).
If she is indeed aro but not ace and is in a monogamous relationship, she’s likely not in the best situation for someone with those leanings. It sounds to me like she wants out of the relationship but isn’t willing to be honest about it and is trying to get OP to end it.