Breakup / relationship advice (How do I stop thinking about him?)?

I' ve been dating my ex for 3 years when I met him there was another girl that he liked but she was involved with someone so he asked me out..

since we started dating this girl started calling him texting him flerting with him.. it drove me crazy I just couldnt bare it.. he also flerted back with her..

after many fights I gave him an ultimatem its either me or her.. he didn't responed but he didn't stop talking to her either. So I broke it off.

He tries to call me but I ve been strong thus far.. but now Im afraid I may have made a mistake.. I love him so much but in my heart I know he loves her and he was only with me because she was involved with someone.. how do I stop my self from replying to hom please help..
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+1 y
He never cheated on me with by the way...
Breakup / relationship advice (How do I stop thinking about him?)?
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