Not happy

How do I tell my husband that I'm just not happy in our relationship anymore? I'm by no means leaving him. I just need to know how to get that spark back. It's like we are roommates more than husband and wife, and we don't even sleep together. He works nights so that's also taken a toll on our relationship. I just need advice on how to tell him I'm not happy, without him thinking I'm leaving. Because I'm not.