How do I not catch hep c from my partner?

Very protected sex. First your partner has to find out if he definitely has hep c, given the options to treat or not to teat, but understand fully the implications of having this entity, and possible complications on the future. The expert would answer in detail your question (you both should go), as a general answer, if quality condom is used, should be protected. In the medical field, nothing is 100%.