Should I call him out on this?

I met this guy from a dating site and we've been dating for a while, and we're almost in a de facto relationship. We've also talked about marriage. We'd both mutually decided to deactivate our profiles from the said website. I did, but when I went on it out of curiosity to check whether he did, I found he had been on there just the night before. I asked him whether he still liked me (by text) and he said yes. He asked me why but I didn't reply. So I was wondering if I should bring this up to him? And would it be better to tell him face to face rather than by text? Or do I sound too possessive?