What makes you say IT'S OVER?

i had bad experiences before with exes who are habitual liars and cheaters. i kept on forgivig them but they just never change. i tried hard to keep the relationships going. but still, nothing seems to get right no matter what i do. maybe because it's only me spending efforts to the relationship. one way relationships won't work long and won't last a lifetime. so, when i see that i am always in tears and in pain rather than being happy with the man i thought who can love me, i just give up and start living my life on my own again. better to be alone than get hurt over and over again.