Have you guys had any tests done to check your LH/FSH levels? For you, FSH would be responsible the production of sperm, which is then added to the fluid produced by your prostate gland and seminal vesicles - making semen.
For her, the FSH would be responsible for the production of eggs in her ovaries.
If you're low in FSH it could be contributing to a low sperm count making it harder to conceive. If her FSH is low, her ovaries might not be releasing eggs every month. Women with low FSH sometimes only release eggs a few times per year.
LH would cause her estrogen to increase, promoting a better environment (in the uterus) to support an embryo. If her LH is too low, and you guys do happen to get pregnant, her uterine lining will fall out and she will miscarry. This might even appear like a regular period, when in fact, you two did conceive.
I think you guys can get LH/FSH tested for not that much money online. Worth taking a look at if you're trying to get pregnant. It might also be worth it to get an ultrasound on her ovaries to check the follicle count.
Good luck!