beta
I hope I am wrong, but I feel like Professor Lee Chungyoung is Lee Yeowoon's father. So, if that's the case than our MC's boyfriend is the son of the professor he is sleeping with...
The reason I think this is:
1. They have the same family name (Lee)
2. The professor mentioned he has a son
3. The MC mentioned earlier in the story that his BF only had one parent and the professor mentioned that he was a single parent...