EXCLUSIVE

Amber Rose and her new boyfriend, Monte Morris, are serious ... so serious they've decided they're gonna be in an exclusive, committed relationship.

Sources close to the couple tell us they recently started telling friends they're no longer dating other people. The first pics of them together in public surfaced this week.

We're told they met through mutual friends over a year ago, but only started hooking up last month ... long after she and 21 Savage broke up. Monte only told Amber how he felt AFTER he found out she was single.