She tells ES Magazine ... Kanye had a lot of unresolved issues he had been dealing with at the time -- “It just seems like he had a lot to work on, and I just don’t have time for it or energy ... I don’t have the bandwidth or emotional capacity for it. I’m proud of myself for that."
On top of that, Julia says she couldn't keep up with the rapper's fast lifestyle once "real life set in." Flying around the world at the drop of the hat does require a pretty open schedule.
Julia added ... had she been the same person she was before having her 1-year-old son, she probably would've held on a lot longer to the Ye relationship.