The Lovers is the card of love, of love triangles and choices. It's about acknowledging who/what will complete us and about making (or not) the choice to pursue the object of our desire. The Nine of Swords is the card of extreme stress, nightmares and negative, external influences. It is also a card of painful endings. The Lovers and the Nine of Swords combination has a tone of finality and often manifests its energy as a dynamic that's rather disruptive.
The elements of the cards are Air (Lovers) and Air (Nine of Swords). Two Air cards can generate a quite powerful and intense combination. In their negative expression, these two cards will bring sleepless nights and feelings of restlesness. On a more positive note - and provided the surrounding cards lessen their negative impact- they will act as a metaphysical cleansing of the psyche after a long, testing period.