I'm a member of a happy couple. My wife and I...
- keep separate bank accounts. When we share an expense, like the rent, with both contribute. Some people are astounded (even offended) that we do this, but in 18 years of being together, we've yet to have a single fight over money.
- play together. We play traditional games, like chess, but more often we talk in silly voices, use socks as puppets, etc. We have a pantheon of characters that "live with us."
- keep in touch throughout the day. While at work, every couple of hours, we check in via email, phone or IM.
- spend a lot of our alone time together. We both love sitting on the sofa, doing our own thing. My wife may watch TV while I post answers on Quora, or she may do a crossword puzzle while I read. It's nice to be in the same room together without any expectation that one of us has to amuse the other.
- work on projects together. We run a theatre company, in which she acts and I direct. So our major hobby time is spent together, building stuff together. We do the same with home improvements, cooking, etc.
- plan surprise treats for each other. Part of me is always thinking about presents I can get her, experiences I can surprise her with, practical jokes I can play on her, etc. She thinks the same way about me.
- allow each other to talk about anything. Neither of us is easily offended. She can say anything to me that she wouldn't normally say in public, and I can do the same with her. I completely trust that she's a good person, and she feels the same way about me, so we can even vent really ugly stuff around each other, and neither of us judges the other based on it.