Most Helpful Guy
Just ditch him and go cold turkey permanently. Disconnect forever. If you are legit about your emotions and feelings for him then facetime anyway and if you feel you two click, and if it's local enough you might be able to date in real life or something, but that's entirely on you.
Were you two "dating" in a game such as "Second Life" or something for those 4 months? Because it sure sounded like it.
You could be like "it's time to come clean and I need to tell you the truth" and then you tell him the truth that you're a catfish and just wanted to have fun, but had no idea where it would lead to but the fun ends now because if you know that it is impossible for you two to ever meet in person or be together, then it's time to say goodbye forever before both of you get so emotionally attached to each other and become butthurt entirely over the ordeal. And then you two just disconnect from each other forever.
4 months of dating that isn't even in real life is hardly any real relationship, but if this had been ongoing for a year or more that really is bad for the both of you. If it was local enough, you both can just try and meet up and talk or go grab a coffee and bagel or something.
Most Helpful Girl
I will never understand why people use other people's photos and pose as someone else... even if they say to keep their identity "safe"... if that really was the case, you could easily have said just that and not sent anything at all... or better yet at least a snapshot of your body or a hand and such... but using someone else's face all together is just awful.
you get what you deserve.
Most people who say this type of story do it with the purpose to "IMPRESS" someone else, with someone else's "looks" because you probably don't find yourself attractive at all.. Most likely that girl you showed him is 10 times better looking than your real self... which would prove my theory. ...
Anyone reading this, if you plan to be a cat fish, choose to steal someone's photo who is LESS attractive than YOU, so in case that you DO become interested in someone who fell for the fake photo, at least when they see the REAL YOU, they'll be blown away on how much better looking you are than the photo you stole.
My best advice is to just be honest and say it... If things go wrong from there, then it simply was not meant to be. It's sad though if you are that much less attractive and cause this person some emotional confusion/stress/saddness... etc. etc. etcc...