No it doesn't.
Sexism is prejudice or discrimination based on a person's sex or gender.
https://en.m.wikipedia.org/wiki/Sexism
prejudice or discrimination based on sex
https://www.merriam-webster.com/dictionary/sexism
prejudice, stereotyping, or discrimination, typically against women, on the basis of sex
https://www.lexico.com/en/definition/sexism
prejudice or discrimination based on sex or gender, especially against women and girls.
https://www.britannica.com/topic/sexism
actions based on a belief that particular jobs and activities are suitable only for women and others are suitable only for men
https://dictionary.cambridge.org/us/dictionary/english/sexis...
What definition of sexism are you using where discriminating against what sex you want to date isnt sexism?
No it doesn't.