1. When you’re alone together, you get the calmness and satisfaction of being alone, and the social fulfillment of being with friends. It satisfies both your introvert and extrovert needs. It’s really nice.
2. Home. It feels like home.
3. Peaceful. There’s always someone who has your back when you need it. If you want company, emotional support, laughs, etc they’re there. You know each others bodies well, fall into a groove, the sex is great. Being around people is exhausting and draining, but this person is exempt from that, somehow. They’re just safe, and warm, and comforting. Loneliness is rarely, if ever, felt.