Quote from Ghost of Cutten:
But a respectful and caring relationship with no passion is doomed. One or both will cheat, or at the least feel very unfulfilled and trapped. That is why there are so many sexless marriages that end in divorce. You are ignoring the sexual component.
I thought it was implied but yes, you need to have regular sexy time. Also, trying new things (not necessarily sexual!) together is a great bonding tactic.