If you're in a love relationship with Aquarius, you're already best friends. As such, your partner will probably tell you if he or she has grown bored or fallen in love with someone else!
If not, Aquarius could become even more distant (which is hard to imagine). If the Water Bearer feels trapped, they'll try to break free at any cost, and that includes ending a close relationship.
That's how much independence means to this sign! And don't expect any rapprochement down the road. Aquarius faces the future - always - so when it's over, it's over.