OP,
Although monkey branching may work at times, look at what being cautious and polite has done for you. Pedistalizing and overthinking what to do next, how to get her, etc. On this path you may get her at some point, but with a lot of patience and smooth, calculated moves. Girls with boyfriends are more likely to cheat on them if you tell them you aren't looking for anything serious, just something casual. Now she is able to have her cake and eat it too, with far less drama and soap opera crap. I love being rejected by girls with boyfriends or husbands... It hurts their ego when a bold confident man isn't afraid to tell her exactly what he wants and isn't phased by her relationship status.