As he wanted 50/50 the arrangement is Monday/Tuesday OP
Wednesday/ Thursday Twatoo
Then alternate Friday to Sundays I think.
Whilst it’s tempting for everyone to speculate what he’s been pursuing (especially with the parking fine). I urge you to be indifferent and not look for answers. Let it go.
Imagine both of you on on different sides of a dimly lit stage with spotlights and keep shifting the spotlight from him on to you.
You might get explanations and insights but much later on. It’s far better to accept the situation and focus on you. He showed clear signs (especially after the twins) that his fulfilment lay elsewhere and effectively he was ‘wasting his life’ with the family. There are men who genuinely take joy from family life but they typically have better internal self-worth.
Just accept he sees himself as the highest priority. Once your family increased to four he had just had enough and fancied the opportunity to reinvent himself.
My ex was similar. The excitement of reinvention may seem to bring them a veneer of new ‘happiness’, but in my ex’s case it didn’t last long, soon he was trying to reinvent himself again. Changing partners, jobs, accommodation always seeking to blame external factors for his own internal discontent.
But that’s up to him now, not you. Focus on you. In your time off can you plan time with friends and play dates with other families over the summer, beaches, ice cream, sandcastles, pond dipping?? Give the children a summer of happy memories. You want the legacy of “even though your Dad had left that year, we still had a fun summer in 2026!