Was I right in this situation or not?

For someone who keeps cancelling on you, you're putting too much effort into a sort of, platonic friendship. If you really want to hang out with this guy, ask him to invite the girlfriend too. And do this when you see him, not in a text or over the phone. If he appears flustered and makes excuses, you know he's doing something his girlfriend wouldn't approve of and you should cut ties beyond clmates.