Strange behavior.

So for about two weeks now my husband has been on the couch. No warning or reason presented itself before he started doing it. He hasn't touched me since. No hugs or kisses. But is otherwise completely normal. I've tried to get him at least back in bed to no avail. I lay alone crying until 3am. He knows but never comes in. We have had a rough patch almost 3 years ago. I thought things were so great now and never been better. Than bam out of no where this happens. I feel like he's trying to detach himself from me all of a sudden. Physically and emotionally. I tried kissing him last night and he looked away but was letting me. I stopped and said do not look at me that way. He noticed obviously I was upset and grabbed me firmly by the chin and said you know I will always love you. That was it. I'm so confused. I absolutely know he is not cheating. Not possible and not a doubt in my mind about that. When he talks about the future he includes me. So I don't understand. I'm exhausted. I can't sleep my anxiety is so bad I can't function. I don't want to be the last to know I'm being left. I don't even want it to end.