It's not that men fall in love in our absence...
It is that the love they already feel gets a chance to rise into their body and heart's consciousness......as men are usually more prone to being disconnected from their emotions- at least as compared to women who are societally encouraged to express emotion frequently.
When you allow that space after togetherness and are ok if he takes a few days to get back to you, he is given a chance to come back to himself, and focus on his needs (something he will perceive as stability and actual love from you), first physical (if only given a short amount of space), then emotional.
Once he's had a chance to miss this terrific woman that has touched his heart, his tender, achy, "missing her" feelings come into full view.
This is when he REALIZES his feelings are a lot deeper than he had thought and deepens his desire for commitment.
As he dreams of seeing her again, his masculine begins to formulate a better offer for her as an act of devotion....deeper demonstrations of his devotion, love, service to her and commitment. Re-energized to pursue further depth in the relationship with her, he comes back hoping to see her smile and warmth again and connect to the realness of her true heart.
And so the ebb and flow of this cycle some wrongfully call push-pull, moves forward.