Since your fallopian tubes and partner's semen analysis are normal, this is considered unexplained infertility. If this cycle with enclomiphene, estradiol, and norethisterone does not result in pregnancy, the next step is usually monitoring ovulation closely with ultrasounds. Your doctor may suggest continuing ovulation induction for 3 to 6 cycles, often combined with Intrauterine Insemination (IUI) to increase the chances of conception. If IUI is unsuccessful after a few attempts, or given your three-year duration of trying, discussing In Vitro Fertilization (IVF) would be the next recommended step. Stay positive, and discuss these options with your fertility specialist to customize your plan.