"Shailene tried to give it another shot and was spending time with Aaron," the insider shares with E! News. "But she quickly saw that everything was on his terms and nothing was going to change. There was no reason to continue and she's done with it again."
E! News confirmed in February that Shailene, 30, and Aaron, 38, had split. "They are two very different people," a separate source told E! News at the time. "They are both focused on their careers, but it took them in separate directions."
The second source added at the time that while they're no longer together the stars remained "supportive of one another and on good terms."
In fact, the duo was on such good terms, they continued spending time together after their split news went public—from stepping out in Los Angeles together to attending his teammate David Bakhtiari's wedding in Santa Barbara, Calif., in early March. A third source told E! News at the time that Shailene accompanied Aaron only to "support" him.
"She's not wearing the engagement ring," the third insider added. "They are testing the waters."
Now, despite trying to rebuild their relationship, it appears as though the former couple is moving on for good.
E! News has reached out to reps for Shailene and Aaron for comment.