The missing piece from all of this is, of course, asking Ayame about her background and such. He doesn't even have to be direct, but that information alone should be enough to come to more accurate conclusions.
Okay yeah, him using the words "used goods" over and over in his head is a bit icky. I don't really have a problem with him wanting a virgin only or his mindset, but thinking she's "used goods" is too far, it's way too dehumanizing.