In serious need of advice

So and i have been together for 6 yrs, live together and have a 3 yr old. Lately I've been really distant because I've realized 2 things: 1. He wants more kids and i dont at all and 2. I love him but im not sure im in love with him anymore or if I ever really was. I feel like on my end the relationship is over but I know he would be completely blind sided. I dont want to keep dragging him along if I cant see a future together anymore and I dont want us to have issues later because of the kids thing. I've never had to breakup with someone. How do i handle this situation? He's the only real relationship I've never had and Im afraid to break his heart but I know this would be the best thing for both of us. Please help, and please no hate I'm very emotional about all of this.