I think you need to disconnect from him completely. To be honest i'm not sure how it even got to this stage for you both - did you at no point discuss what your true intentions were? It seems bizarre that this level of contact between two adult people didn't actually include any serious talk about what your relationship actually meant or how you really felt about each other. To be honest it sounds as though you don't actually know each other that well...i mean only talking a few times year and one actual visit? I'm not sure how that's suitable grounds for marriage.

I would reevaluate what online friendships/relationships can actually give you and if you're serious about marriage etc. focus on finding someone you can actually meet with and get to know properly. Don't rush into something out of desperation. If you have to move to him or he has to come to you things could become extremely messy - why even do any of that if he's just randomly decided he wants to marry you without any lengthy discussion on the matter? Move on and allow this person time to realize that in a civilized world marriages and relationships are serious and can't be decided on whim.