Another woman's hair around his dick?

So I've been seeing someone, not sure how to define it yet but we said we'd both not sleep with other people, for our peace of mind and sexual health.

Today, I was about to give him head so I was touching him and felt hair on his dick. I pulled it out and noticed it was a blonde hair. My hair is black. He said he swears he wasn't with anyone else, and that in his house the towel he used probably had hair on it and when he dried himself off it probably got caught in it.

I'm not about to stalk his family to make sure someone recently dyed their hair blonde but from what I know, getting long hair around your dick is usually because of living with a woman or having sex/getting a bj from her.

We haven't had sex in 3 weeks because of our busy schedule. Should I believe him, or is he lying? I have never seen another hair on him other than mine before....