I don’t think it’s a bad thing to ask someone to wait for you. Especially if you’re both feeling the same way. I guess it just depends on how open you both are to the idea that it may not work out as planned. But it’s definitely something that you should talk about. Specifically since he did come to visit you and you everything, it might have been a good conversation to have. A lot of people who meet online agree that if one of them was to find someone else a long time before they could be together permanently that they would back off and wish them the best. The important thing is to just be happy for them if that happens like you are. I hope it works out for you! :)