
That’s a great question! Partner integrity is in fact a major aspect of not contracting STIs as a whole. I won’t speak for OP specifically, but for general knowledge, barrier-based protections (ex. Condoms), performing proper genital hygiene, and regular STI testing can help limit exposure and severity of the infection should one contract it.
In terms of antibiotics, there are common ones that can be given to treat chlamydia. Doxycycline is a common and often provider-favored, and azithromycin is provider- favored should the person wishing to treat this specific STI be pregnant. It’s important to take the full dose and prescription of whatever antibiotic you’re given and to abstain from any form of sex until you have been properly tested and come back negative for that STI.