How can I get him back


Soo weird title but a guy and I dated back in January broke up with me bc of a dumb rumor. We started talking again and figured out what really happened. Since then we have been inseparable for about a week. Seeing each other every day and falling asleep together every night, and just running errands together was the best. Although, my sister is best friends with him and she told him that she can't trust him if him and I date. And she doesn't know we were doing anything more then being friendly. So him and I were talking about what to do and he doesn't want to lose her as a friend. So he said he'll think about it but then said he wasn't emotionally ready for something and wanted to slow down. I'm not sure what to think, but he knows how I feel, and I just can't lose him again over something so silly. I'm crazy about him! Help me, what can I say?