Why do guys breakup with women when they have a lot going on or are stressed out?

I was with my ex for 8.5 years. Over those 8 years we've broken up 3 times (not including this one) the breakup were not because of cheating, trust issues, abuse or anything like that. He's always broken up with me when he has a lot going on and doesn't communicate that he needs space or anything.
Am I head over heels or dumb to want it to work but in the right conditions this time?
Why do guys breakup with women when they have a lot going on or are stressed out?
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