they have fallen in love for more than half a year

fall in love 爱上某人,是个时间点发生的事情而后面有more than half a year超过半年,是个时间段显然不对,因为爱上某个人不可能要半年的时间所以应该用 been in love 陷入爱中。。才对所以整句是they have been in love for more than half a year。