Been talking to my ex using a fake account cuz he lied to me about getting married. It's been 6 mnts & wants to meet (as a friend). I feel bad. Should I tell him? Will he hate me for it?

I understand that you feel bad because of how your ex made you feel. I can understand your need to find out more about him with the fake account, as you were worried about his actions. This is totally natural! It is not possible to know how he will react if you tell him that you were spying on him with the fake account. However it's a good thing that you are examining your own emotions and how this situation makes you feel. What other kinds of emotions does this situation make you feel right now? It's a good idea to examine this further.