The worst hurt is about sensing what might have been, and the most penetrating love scenes are those in which both parties feel this acutely but don’t (can’t, won’t) put it into words. The finales of The Way We Were and Bridges of Madison County had this current (as repellent as this observation may be to the HE hipper-than-thous), and the finale from Elia Kazan‘s Splendor In The Grass had it in spades.
The less you say with dialogue and the more you leave it up to the audience, the better.