According to Osho, if your marriage has been almost entirely misery for years, leave it—sooner is better. Marriage is a mix of joy and pain; if it’s roughly fifty–fifty, stay, but a hundred-percent misery is neurotic. Don’t hide behind God or ideals: God isn’t a sadist. If joy never happened, the 'divorce' merely acknowledges no real marriage existed.
If your marriage is only making you suffer, it’s okay to leave—don’t stay from religious guilt; choose some real joy in life.