When a Korean man is in love with you, you will know it. They can't hide it. They will show it in the most surprising ways sometimes. You can probably expect flowers or silly little gifts. He will probably get you a beeper and pay for it just to keep in constant touch with you. He'll take you places, help you shop, be your translator-on-call. He'll be there for you in every way that he can. But there are many issues to deal with when dating Korean men.
For one thing, you have a 99.9% chance of having to accept that the love of your life hasn't told his parents that you exist, or if he has, he has told them that you are his English teacher. Koreans tend not to introduce their boyfriends/girlfriends to their parents unless they are planning to marry. Also, it can be very difficult for Korean parents to accept that their beloved son wants to eventually give them grandchildren with foreign blood. If your boyfriend is the oldest son, or worse yet, the only son, be prepared for many arguements and lots of tears.
You may not be able to call him at his house. You will have to be understanding when he needs to go home every night to his parents. You will probably meet his friends, but on such outings, you may be the only one at the table who doesn't speak Korean. Dating a Korean man is very hard emotionally. Loving one is even harder.
If you both fall in love with each other, you have a difficult storm to navigate through. Look at it this way. Your boyfriend will eventually have to make a choice between you and his family. Whichever choice he makes is going to tear his heart in half. And do you really want a guy who is easily willing to give up his family? Mightn't he later give you up just as easily? Your boyfriend is in a very difficult situation with a heart-breaking decision to make. Try to be as understanding as possible. Constantly pointing out that YOUR parents have known about him for months is not going to help the situation. You are dealing with a difference in culture.
Something else that you will have to consider is, if you get married, where will you live? Can you give up your home? If you cannot see yourself giving up your home and country and leaving your family, then surely you can see how difficult it is to ask him to do that instead. If fact, there are so many issues around this, that I could probably create another website devoted to just that.