Stressed about my relationship, what to do?

I don’t know how I feel about my relationship anymore. It doesn’t feel as fulfilling and exciting as it used to be. I don’t feel as desired or wanted as I used to. I have been home alone in our apartment for 4 days now and it doesn’t feel horrible to be here alone. I do kinda miss him and he’s coming back this weekend. I’m not sure what to do about it as i’m very hesitant to leaving. I have been thinking about it but I don’t know if it’s the right decision, and I don’t know if i’m ready for it yet. I feel like I expect more from a partner, he has done and said things that I don’t want from my boyfriend. How do you know if it’s right to leave? How do become brave enough to talk to him about it, or leave him? I don’t feel like i’m ready to leave, even though parts of me feel like it’s the right decision.