She would never say it was fate that Worf's wife had been murdered. But perhaps it was fate that he returned to her just as she and Will were finally sorting things out between them.
Not to say that it was easy, or that she had even expected to find herself still in love with the surly Klingon. But, somehow, it had worked out, and even if Will and Worf didn't love each other the way they loved her, they were willing to accept that they both loved her, and that was enough.
When Will was offered the Titan, he made sure that both Deanna and Worf could transfer with him, and put in a special request to increase the size of the captain's quarters. As such, when the day is finished and the captain and chief of security are no longer required on the bridge, and when the counselor's appointments are all finished for the day, the three of them retire to their shared quarters.
They don't always make love, and when they do, it isn't always as a group, but they always fall asleep together, Deanna safe between the two men who hold her heart in theirs.