How do you know?

How do you know a relationship isn't worth saving? My hubby and I have been together almost 8 years, I am so tired of him and his apathy to everything. Does couples counseling work? Is it even worth trying to save? I don't want this anymore and I'm tired of trying for something that isn't worth my time. I am trying to improve myself and he isn't at all, I try to diet and he shoves food in my face as temptation. I try to exercise and he makes fun of me for wanting to look better. I am so disgusted by his presence, his noises and eating habits and attitude. I just want more from my life, but I am afraid to give up on this because what if I can't find anything better? Sorry for rambling, he invalidates my feelings so often I don't even know what feeling are rational anymore and what are overly emotional for no reason. I just want to start over but don't know how. What if it isn't better than this?