Why would he make me think this?

I asked my fwb if he was seeing anyone else, because he had asked me first if I was and I told him yes. So I asked him. He told me he wasn’t. He referred to me as “my girl” in a conversation one time after that. So fast forward a few weeks and I told him I wasn’t seeing the other guy anymore. He barely responded to me and didn’t seem to care.

So what I think of it is, he is seeing other people, and he doesn’t want me to catch feelings for him. So then why didn’t he tell me the truth when I had asked? That would make me definitely not catch feelings if he had just told me he was seeing others too.

Does anyone get his logic??