My old CX500 clutch never slipped. Don't have this bike anymore but I made a lot of miles in the saddle on it.
It might be something simple, like regulation, or bit more expensive like old weak springs and wear clutch rings.
As far as I remember clutch access is extreme easy, so eventually job should be not complicated.
Also when yo have it check if you have leak from water pump seal - this is very common in CX and fix is pain in the neck ...