Men who have a partner look more attractive to women (preselection). Women actively practice hypergamy (wanting someone who is superior to her).

Therefore, the best strategy to get a woman who is on the same level as the man is to get an ugly starter girlfriend. Then with the increased attention from other women upgrade to a plain looking girlfriend. Then finally monkey branch to a woman who he is actually attracted to.

This strategy won't work for women because men will happily pump and dump women they wouldn't commit to, while if a woman sleeps with a man, she would also be 100 percent open to being in a relationship with that man.