Everything is temporary, I know that's a scary thought but it's just part of life. He may have been talking about your relationship but most likely he was referring to something else that's bothering him, even the problems you're having are temporary. I'd ask him to see if everything is okay, he may need someone to talk to and it's best to talk about it if it really is a relationship issue. Unfortunately even the best relationships come to an end so you should definitely ask him so you can rectify any issues before it's too late, the most common reasons relationships end are the passage of time and unresolved conflict since people generally don't like confrontation so it causes the relationships of any kind of fizzle out when it could've easily been saved.