Is it a lie? Or does he knows And won't say

I've been with my boyfriend for a while and I'm 17 years younger than him I'm 30 he's 47 years ago when he was 18 he got married because he got a girl pregnant and ended up having 3 girls with her there relationship ended on bad terms but after that he got in a bad motorcycle accident and his penis and balls smashed into the gas tank at 120 MPH he had hoped the skin of his penis and cut some ligaments but no mayor vesicles so they were able to reconstruct and it works perfectly but I wonder is he sterile I've asked him and he said no but I don't know if he is lieing or he just doesn't seem to know he said his balls got really swollen but no harm I gave unprotected sex with him sence we've been together even on ovulation days and nothing and I don't know what to think or say any advice?