I had to quit reading any FIRE (financial independence, early retirement) blogs because they were full of people headed down this same path: Extreme frugality, bare minimum savings, assuming their lifestyle would never change and nothing would ever go wrong.
Retiring at 30 sounds great, but no one's life goes exactly to plan for next the 30-40 years until traditional retirement age. People change, expectations evolve, possessions wear out and need to be replaced. Living frugally may be fun when you're in your 20s, but it's not so fun when as you get older and your friends want to do things that require money (vacations, hobbies, dining out). Even worse when your romantic partner has different goals in life, as happened here.
Many of the leanFIRE stories have their roots in people who hate their jobs so much that the only thing that motivates them is early retirement. They grind through the job the hate, counting days on their leanFIRE countdown until they can quit working and never look back.
Most of these people would be much happier if they simply invested time and energy into finding a job they enjoy, or at least one that doesn't make them miserable. Even if it requires a pay cut and a later retirement date, it's much better to spend your time doing something you don't hate than it is to grind out a bad job in misery just to reach dreams of early retirement sooner.