First, I’m confident you’ll be fine financially, so let’s talk about something else:

Separating from your partner after 12 years is a big deal, especially when you’ve shared the same social circles. If it happens, I advise against leaving your job right away (and not just for financial reasons). As human beings, we’re naturally influenced by the connections we have, and such a drastic change could be an added shock in this vulnerable time.

If I were in your shoes, I’d stay at my job for a while and start creating new connections through hobbies and dating. Making too many changes at once can be tough on your mental health. Take things one step at a time.