习惯不曾习惯的习惯会习惯爱上不该爱上的爱上会爱上
[xí guàn bù céng xí guàn de xí guàn huì xí guàn ài shàng bù gāi ài shàng de ài shàng huì ài shàng]
A complicated phrase which means 'Habit of falling in love with someone who shouldn't fall in love becomes a habit'. This implies a person who tends to repeatedly get involved with people knowing it may not be right.