that only happens when you sell dreams to these women or when you're not being true to yourself. that's not to say i haven't done this (mostly on accident) but it's least likely to happen if you're upfront and honest instead of focused on just trying to have sex with the girl and doing whatever it takes to have that happen. i haven't done anything like that in years and the last girl i did that to was selling herself some dreams. i actually told her up front what was going on in my life before we became sexual. while that doesn't remove me from blame (because it was still selfish of me to do that knowing she wanted more) i can say i learned a lot from that experience: when you really don't want to be with a girl, it's best not to deal with them unless you know for sure it's something short-term.
also, you know when it's right if you pay attention and you use every opportunity to learn. however, most people aren't concerned with that, they think the end is getting the girl you wanted right then and there. so it's a "by any means necessary" approach for self satisfaction through others...