Should I be mad that I saw that my boyfriend is on Plenty Of Fish?

So, I'm at my boyfriend's place and he is letting me use his laptop while he's gone for the week since he's going out of state for a regional board for the Army. Well, I went on yahoo, and I am so used to just going there and automatically going to check my email since on my computer, I'm always logged in, so that's what I did without even thinking, but instead of going to my inbox, I was directed to my boyfriend's inbox. It didn't occur to me until I saw the kinds of email in there. There was stuff from Facebook from people from his family and friends, which I definitely wouldn't get. It was no big deal, but I also saw that he got quite a few messages from girls on that one dating site plenty of fish. I checked the dates they were sent, and they were sent during the past few days. So, I decided to check out his profile on there, and I looked under his relationship status, and it was marked N/A. But, I was wondering if maybe he created his account when we happened to break up that one time and just maybe forgot to change his relationship status on there... I was thinking about taking a look at the messages, but I'm afraid to do so... I know he hates cheaters, and he knows I hate them to and would drop him in an instant if I found out he cheated. And he still tells me he loves me and still plans things in the future with me and buys me stuff that I like even if I don't ask for them, cuddles me and holds me and kisses me... I don't see any differences in his actions or behavior at all. I don't really know what to do, though. Any advice?
Should I be mad that I saw that my boyfriend is on Plenty Of Fish?
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