How do you know it's time to end a relationship?

ok so I been with this guy for 4 years now and things have changed hes always on his phone he never talks to me about anything I pay all the Bill’s and work hard for what I got my question is what should I do he dose not work the place we rent is under both r names I pay all the Bill’s and he just sits around and dose nothing he leaves to go out witch I’m ok with but I’d like help around the farm but every time I ask him to do something he freeks out and says don’t urself he has all these bag plans that he wants to do but he won’t do anything to get them done I’m at my waist end im stressed out I have a felling hes cheating on my with someone that’s 30 years older then him but I cant prove that he is I just dont now what to do anymore I love the guy but I hate that we r falling apart what can I do to get his attention back or should I just tho in the towel and walk away and let everything go homeless I’m at a loss