Why don’t guys ever take me serious in relationships?

I just got out of a relationship not too long ago
We were together for 5 months before we dated we were friends for about 2 years he stayed at my place for about 2 months while he was looking for a new place and cheated on me with his ex. I took him back a few months later his cheating caused us to argue a lot because I did not trust him anymore in the end he left me for his ex and admitted to never being ready for a relationship. all of my other relationships before him were all bad. I was a good person to all of them but I always got cheated on played with and used. and every guy I meet now try to use me for sex or waste my time and a few of them were already in a relationships. All of my sisters cousins aunts and some of my friends are all in relationships what am I doing wrong in my relationships?
Why don’t guys ever take me serious in relationships?
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