Secret Instagram account..should I run a mile??

It's gas how many people comment and get up in arms without actually reading through the thread.

OP cleared up the ambiguity about whether she had met him or not, and she cleared it up about four times.

Also:

Homerjay2005, the OP herself said the issue wasn't about him having an instagram account, it was the fact that he lied about it and the way he lied about it. I don't think he's sleazy at all, but I think it's pretty clear that he spends a lot of time using instagram, so to lie about it so vehemently is a red flag. And yes, everyone tells little lies now and again - but to do that so early on just says that he's starting as he means to go on. Everyone has a right to their private life, but that doesn't mean you get to lie about your private life and expect a potential partner to respect you.

I don't think he's sleazy, but there would be something very off-putting to me about a guy commenting and liking someone's pictures all the time - and yes, age does make a difference to this if it's a potential partner: young lads can get away with it but as guys get older they should have more sense as to how crass it can look, for the same reasons that we tend to hold mature men to a higher standard than younger men in how they conduct themselves. And the same goes for women in my book.

And I don't think the OP's behaviour is obsessive at all (it went on longer than perhaps it should have, but that's just me). To paraphrase ursushorribilis, in the cold light of a computer screen it can look over the top, but think about it: you meet someone and you really like them. You find out they lied about something. You have complete access to the thing they lied about and it will be several days before you can bring it up with them... I'm sorry but most people would fall into that trap quite easily.