Should I say ';it's not you it's me'; to break up with a girl? why not?

If you break up with someone and you tell them it's not it's me how is that bad when that could be the real reason. Maybe you don't trust your partner or feel feel insecure which is pretty much goes hand in hand. Maybe you don't feel connected to your partner anymore so that is technically still YOU. Do you actually think people 100 percent truthful? Should you say ';I don't think it's working anymore'; which is just as VAGUE as saying ';it's not it's me';.Should I say ';it's not you it's me'; to break up with a girl? why not?
Mayb you should say the reason instead of just, it's not you it's me.Should I say ';it's not you it's me'; to break up with a girl? why not?
It's cliche, but it's better than most cliches so if you can't be more specific, go ahead and use it.
nah just say


';***** its over.


now get the **** out of my house and on the street..';';