Scared, is this normal? ?

I'm sort of with a guy, it's all hush hush and has been for months, he says he feels somethings missing which makes it all so unofficial, but for months now ive felt so strongly and stuck it out, never meaning for him to end up caring so much as I did, but it's not as obsessive, what I feel, but Im still super happy when im with him and I'm sure if we properly date I'll be happy, but im scared I'll stop caring, and I dont want too. People tell me love is a feeling that settles and it becomes less an obsession and more the norm when you're with someone long enough, and since I've never adored someone so much for so long, I hope it's just my feelings settling in and just me panicing. I don't want to hurt him :(