I want to strengthen the words of Zuzak. There are many reasons why couples have trouble getting pregnant. Sometimes there is a specific problem with one of the sides (Male/Female) and many of these cases are very easily treatable, but a doctor needs to see you for that. The truth is there might not even be a problem, and it may be just a matter of timing during the month. A doctor will be able to give you answers in that direction as well.
Hope you have the best of luck. Best regards.