any recommendations for yaoi/shounen ai with playboys/womanizers?

Hi :o)
I thoroughly recommend the long-running "kemono" series by Fujisaki Kou-sensei, which has multiple playboy semes - actually, if I remember correctly, most, if not all, are playboys. The link is for the first in the series, but if you look at redpanda42's comment (first on the page) they list the titles in order. Happy Yarou Wedding introduces the second couple, Chiharu and Kazuki, who make up the foundation of the rest of the series (the first couple does not appear elsewhere).
http://www.mangago.zone/read-manga/happy_yarou_wedding/

following!! :)