I need help

Ive been trying my hardest to stay off here and google in general but today unfortunately ive given in to compulsions. Im really struggling to even explain how I feel. When I started dating my partner I thought id found my forever. He is so different and healthy compared to any other man ive been with and its so safe in my relationship.

Im starting to realise I may have an avoidant (probably fearful) attachment style. My feelings feel like they have genuinely changed recently and it really hurts. Whether this is me coming out of the honeymoon phase or genuinely losing feelings I dont know. It just feels different. I feel no desire. No interest. No attraction. I feel nothing. But as soon as I think about break ups, I feel immediate panic and immense sadness. I dont want to end things with him, whatever the reason is (whether its not wanting to hurt him or that I dont want it to end idk). I feel so incredibly lost. I just dont know what to do.