How true is the saying “once a cheater, always a cheater”?

I have been cheated on by every single guy that I dated. My first boyfriend cheated on me with a girl he met at work during the summer, I still stayed with him and he never reoffended. My second boyfriend cheated on me with his ex, I caught him, gave him another chance, then he cheated again (still with the ex). So in my case it’s been 50:50.

How true is the saying “once a cheater, always a cheater”?
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