Speaking as a non-Christian theist who's got a very strong and beautiful connection/relationship with infinite divine Love, in her own life..?
I do feel like ultimately ALL love derives from that. But the thing is..? You don't have to explicitly believe in it, or see it in that way, in order to have access to it! Which.. by far most atheists AND theists do! For me personally..? My spiritual path has been invaluable, and incredibly beautiful and enriching! But that's not everyone's story... Some people find that Love walking a different spiritual or religious path than me. Some already know it, being atheists. And are already awakened in their own way! Even if it's not an explicitly spiritual thing. Which I 100% respect.
..Some of the wisest, most open, most loving, most beautiful people I know..? Are agnostic atheists. <3