When one person isn’t in the mood, it doesn’t mean connection and intimacy has to stop. It doesn’t need to result in feelings of rejection, tension or distance. Instead perhaps ask “what would you like to do instead?” or "instead could we.....?" Intimacy can be cultivated in many ways, not just isolated to the bedroom. In fact, looking at alternative ways to connect can foster the sexual relationship too. Cuddle up on the couch, give a massage, spend some time kissing.  
So next time one of you isn't in the mood for sexual intimacy, instead of turning away from each other, try conjure up a way you can still connect.