My fiance is having problem phimosis.iis it afect ur sex life.

Phimosis : No, it can be cured. The sooner it is treated the better outcome is likely. Circumcision is an excellent option.

Should be treated: Phimosis means that he can not keep his penis clean which is un-hygeinic for both of you. Places him at risk for future penile cancer & can develop paraphimosis, which is an emergency, during sex. Circumcision is best option, but might respond to applications of prescription strength steroid cream, provided he doesn't have a scarred foreskin. Advise him to consult a urologist.