"It was mutual," the source told E!. "Jack and Lena were growing apart and it just made sense for them to end their relationship where it was.
"They want the best for each other no matter what. They are both moving on," the source added.
The former couple were last seen publicly together at a pre-Grammys party in 2017, almost one year ago. It's no wonder their split was able to remain under the radar for so long!
Wishing the pair all the best during this difficult time.