If a female has chlamydia and has intercourse without protection for months is it certain that the male parter has the std as well?

Virtually certain: Since intimate exchange of body fluids occurs during intercourse, and there is usually direct contact between the man's penis and the woman's cervix where the chlamydia is most concentrated, it is very likely that the male partner has acquired the infection. I would strongly suggest that he be tested as soon as possible so as to detect asymptomatic infection.