How do you know when a relationship is declining

Someone told me a few years ago that when you start to see each other less that’s when you know. It’s just been on my mind because it’s like we’ve been talking to each other less and less. I dont know what’s going on with him or what I did but he won’t open up to me. I ask if things are ok and he says they are. But how come I feel like they aren’t. Why do I feel like he’s checking out and running away from me.

Just so you know, we used to giggle all the time. We spent so much time just making each other laugh and now we don’t. You can’t just end that on me cold turkey like that. Because I wasn’t done. I miss our friendship