80 % of couples conceive in 1year and another 12%in the second year of regular intercourse. If you have been trying for more than at least a year then seek expert advise. This usually includes blood tests for your wife and a scan.semen analysis for you then decide on further course of action. Management depends on all the results as well as the history as to whether she has regular periods,her weight, problems such as thyroid dysfunction etc.. good luck towards achieving parenthood.