<human>: Can you provide a brief overview of the text?

Here's what's going on.

I met my boyfriend on a free dating site a couple months ago. We talked for about a week then decided to meet for drinks. It went well, obviously, and we've been facebook official for a little over a week now. It seems like we have a good relationship: we text every day, get together a few times a week (we live nearly an hour away from each other). 

So what's the issue? 1: I've gained quite a bit of weight this year, about 50 pounds. He is not overweight by any means. 2: I (admittedly somewhat obsessively) go on the site quite often, not logged in, to see when he was last online. Every time I check it says he was 'online today'. Once it even said 'online now'. He does not even have a cell phone so the possibility that he merely has the app is not there.

He is a great, sweet boyfriend in every other aspect. My question is, how do I know he's not just with me because he wants to be with someone? I realize I should probably bring up the fact that I have seen him on the website recently, but how? If you need any more information, go ahead and ask; I'm an open book about this because I want the best advice. Don't be afraid to ask something that might be considered offensive.
<bot>: I'm chubby, boyfriend isn't. He still checks his dating site profile daily. How do I bring it up without looking like a damn fool?