Hi,
Welcome to ehealthforum,
There are a lot of factors involved in a successful pregnancy. You should consider getting a complete infertility work-up done for you and your partner to see if there are any underlying causes for the infertility/inability to conceive. Hormonal issues, problems with ovary and ovulation, uterine problems, cervical or vaginal infections should be ruled out for you. For your partner, semen analysis to rule out infections and to confirm the quality and quantity of sperms produced should be done. Treatment as needed (based on examination and investigations results) would be done to help you get pregnant.
Take care.