What do I do? I need advice.

I very recently started dating someone. He worships me and I love him as a person. He's super sweet and considerate and he's a gem. But he asked me out and I thought I was ready. A bit ago I had broken up with another guy. He was super genuine about his emotions to me but we both agreed that he wasn't giving me what I wanted. I'm in this new relationship now and I'm missin my ex. Even though our relationship as people got really complicated I miss him so much. And I feel terrible because this wonderful guy wants to give me the world and I can't even give him my passion. I want to just see where we go because I know he will stick around until I fall for him. But I don't want to break his heart. What do I do?