If you pay 50:50 when he was earning £100k, presumably you're on good money too, and given you're married... well, you'll have to support him for a bit.
Are you happy with your job, or do you also hate what you do? That would have a high impact on how annoyed I would feel.
Given he quit around the 6-month mark with nothing lined up, honestly, I suspect he's been told to quit or be fired, and he's too ashamed to tell you.
If you've moved into a mortgaged house, at least he quit after the new mortgage was sorted. Silver linings.
Once you've both had some time to gather your thoughts, he needs to explain what the next steps are. He's created this situation by leaving, so he needs to have a plan. As his partner, you should support him right now, but that support has a time limit, or it goes from being supportive to being a mug.