Anyone experiencing low sperm count with partner?

Ashley • Avoiding pregnancy. 3 losses (6, 16, 15 weeks). 1 earth son, Lincoln born at 26 weeks. Just turned TWO & doing great!
After 2 years of trying after our 2nd miscarriage uh and was told he has low sperm count, we have no idea how it happened. Just wondering if anyone has any advice or found ways to boost the count? I've heard zinc and vitamins C?  Thanks!