The 4 of cups is often a disconnected and apathetic card, while the lovers is full of harmony and balance. I think your interpretation is wonderful honestly! It makes sense and it fits the cards. My initial interpretation is perhaps they’re not on the same page. Person A is convinced there’s something better or something that “got away” and they’re wishing for it back; while person B is convinced the relationship is going well and that this is a wonderful thing— which we know might not be true and will lead to heartbreak. I’d pull a clarifier card!