Responses
wh- is this incest?
sounds similar to this, but only the, "met [another] guy, they fell in love but in the end the other guy disappeared? turned out the another guy was his father when he was younger" part: http://www.mangago.zone/read-manga/not_equal/
omg yes it is! thank you so much!
no problem!! glad it was the right one ~ ヾ(☆▽☆)
it has time warp/ parallel thing(?)
where a guy visited a laboratory (not sure but it has buttefly specimens) in a univ and met another guy, they fell in love but in the end the other guy dissapeared?
turned out the another guy was his father when he was younger, but the mc didn't know that it was his father, and the "time magic" only happened in that lab room
(i forgot either his father passed away or not in the present time)