Is the spark dying?

Last month my fiancé confessed that he felt our relationship getting boring and he told me things he wanted me to change on my end such as making the initiative to plan things like dates because he felt like it was always him and I agreed but since then he’s been different… He isn’t as affectionate with me and I find myself being the main one to make the initiative to hold his hand, hug, or kiss him. He has also been rather cold, blunt, and distant to the point that it’s making me feel insecure and unloved as well as unsatisfied when we have sex because it just feels like well... sex, not lovemaking. He enjoys it but I don’t feel him being passionate and for me it feels more like something I do just to please him.

Yesterday I mentioned over text that he had been distant and he confessed that he wasn’t happy (not depressed though) to which I asked if he meant in general or overall and he said that with “eveything” and that he just didn’t feel like talking which really hurt so I told him that I’ll just talk to him in person next time and told him goodnight to which he just replied “Okay fine, goodnight then.” And we haven’t messaged since… I usually text him good morning but I decided to make him initiate talking to me since he’s the one being cold and I want to see him reach out to me and show me he cares but he hasn’t and I keep finding myself more tired and disappointed…

This is the first time in almost 5 years that something like this happens and I feel so lost. He’s always been so sweet with me, complimenting me, checking if there’s any issues with me, and being supportive as well as just being playful and then now he’s suddenly behaving like he doesn’t care. I love him and I want to marry him someday and I’m willing to try to fix things if something is bothering him because his feelings are valid but he has no right to treat me so coldly. With the way he’s treating me it’s making me feel like he just doesn’t want to be with me and it’s making me feel distant too and not excited to see him like before…. But if he’s going to keep behaving like this and making me feel this way… He should just tell me because even though I love him I don’t want to be with someone who no longer loves me.

I’m not sure if I’m overreacting but I just feel so confused and unsure since it’s the first time he has made me feel heart ache… and I don’t like how ugly I’ve become as a person as in insecure and stressed. Any advice?