Syphilis Question

[Dietgor]

Hi! I have a question about a posible infección me and my boyfriend might have, (gay) one of these days my boyfriend seems to have develop a kind of chancre, it is like a sore with kinda white borders and an open appearance in the center that one is located just underneath is penis head, he seems to have one more of these chances near that one, he did not notice those chancres until one day in the shower, the next day I went out and had a VDRL test and it came out as non reactive. He still has not received his test results yet

My questions are, if I have no syphilis syntoms and my test are not reactive would it be probable that I passed syphilis to him?

And if not, could he had gotten it in another way that is not sexual?

Thanks!