Hi. I'm sorry to hear of your difficulties. It seems you need a more aggressive approach if you have been trying for 6 years.
Your wife should have a hormonal workup & you should be retested to see if the sperm is part of the problem or not.
Once you've completed these tests, your doctor should be able to recommend a plan of action, possibly including IUI - intrauterine insemination. If male infertility seems to be more of a problem, then you may move on to IVF and ICSI (even without trying IUI).
All my best,
Rachel Inbar