hey dude, please meditate on what i have told you.
when you let people specially girls into your life yes you will find quite a few that you will nothing for and will have your way. however, you will meet one you want to be with for ever. and if you use her for sex she will use you right back. with out you knowing after the first time you meet her you will be in love. however you wont know it until is to late. the only way to prevent this is to, not use women for sex. this will not just give you good karma but you it will make you happy for a very long time. if you do use them you get bad karma and you will suffer for a very long time. so please take this advice to heart. and feel free to ask me anything
peace