Just not happy anymore 😔

My fiancé and I will be together for 2 years in October. I don't know what is wrong with me lately. But I'm not happy. I still love him, I just feel myself struggling. I've never been unfaithful to him, but we've had a few set backs that took a while to regain my trust. I know I need to talk to him, I just don't know how to bring up the conversation. Just sorta lost and looking for some advice. No bashing please