In my POV, the dreamer haunted by heterosexuality (since he is a gay), but in the other side, under his deepest subconsciousness, he yearn an orgy scene as his sexual variation in his real life.

Furthermore, he still feel uncomfortable with his sexual choise. He want to try having sexual connection with woman. But he feel worry to harm his spouse, symbolized by strong loneliness sign in the dream (he is the only survivor).