Message deleting

My SO and I have been having issues recently mainly because I voiced my opinion about a certain girl he is friends with (he has many other girl friends, all of whom i actually like).

I mainly didn’t like this girl because he went on a date with her before and insists one continuing to be friends with her and that I shouldn’t have a problem with it even though I know that she cheats on her bfs (my SO told me that).

Anyways, I am guilty of snooping before, but today I looked and he deleted the message thread with this certain girl that we have been having issues because of.

I’m not going to bring it up to him that I saw this but I just think it’s very suspicious. Thoughts??