Why there is a lot of white discharge?
It sounds like you are about to ovulate which is the best time to have sex to become pregnant. Some people, myself included get a white discharge leading up to ovulation & then a day or two before (or even on the day) that discharge turns clear and stretchy that is the BEST time to have sex to become pregnant. If you are itching or it has a very strong smell you need to speak to your doctor incase of infection, however that sounds like ovulation to me, especially when it happens every month around day 14 when with a 28 day cycle would be pretty much the time you ovulate. Speak to your doctor if you have been trying for longer than a year without conceiving. They may able to help you with things.