I’d offer her $500 and a free moving truck. $500 (assuming you have it of course) seems generous I know, but throwing some cheese in front of her getting her to leave compliantly is very likely going to be quicker, easier and quite probably cheaper than any other solution.
Get the keys to the car, secure all your valuables.
Don’t have sex with her again. Seriously, just do not have sex with her again. “Whoops I forgot my birth control pills” = $100,000 – $200,000 worth of child support over the next 18 years.
If all you’re looking for is a hook-up, then it’s no problem to make the first move. But in terms of getting to an actual relationship, it’s not the greatest of ideas to make the first move if you’re a female. You’re better off displaying higher value and waiting it out.
However, I’m not convinced that not even looking at them is of value. That’s running into the “cold distant bitch” zone. Be pleasant, engaging and fun, but he’s the one that should be trying to escalate things – typically an isolation play. “Hey, you want to go get coffee?”
The other way it works is if a couple meet and she is on birth control pills, once she’s off them to try and have kids or use a different method, she can feel less attracted to her partner. Plus she may not be as genetically compatible with him as she could be, leading to poorer outcomes with pregnancy and the baby’s health. Before anyone panics though, bear in mind that these are simply influences on the outcome and not destiny. Plus there’s still a lot of science left to do on this stuff.
The volume of testosterone in men does take a two-step dip down after marriage and the arrival of a baby Primarily the male has a lot of testosterone to assist in engaging in risky mate finding behaviors, but having reached the Body Agenda goal of actually getting a mate and having a child, the Body Agenda turns to a more conservative strategy of defending what they have. Thus men tend to become more settled and calm after getting married and having children. Or put another way, men who have no offspring have from a Body Agenda perspective, have nothing to lose. While those that have offspring do have something to lose, so they play it safe.
Testosterone drop in aging men plays a role in diminished libido, energy levels, mood, impulsivity and a ton of other things that are generally sexy. So the results of lower testosterone levels can be an attraction killer for the women. And yes, exercise, diet and weights can increase the testosterone level in men, so generally a good thing for overall male health.
I don’t know your daughter or her friend, so I have no idea why the difference is as it is. High school is an awkward age for some kids, and some peak early. You never know how people will turn out over the very long haul.
And yes, sex is very animalistic. It’s a very humbling thing sometimes to have your body suddenly want to lurch itself toward someone you know isn’t a good idea to be in a relationship with, and then become non-reactive with someone you know is a good idea to be in a relationship with. The trick is finding that person that is the balance that can do at least some of both.
Which brings us full circle to whether or not a woman should make the first move. If she has to make the first move, he’s just not that into her enough on a Body Agenda level to be motivated to make the first move. That’s not particularly fixable either, so she can waste her best years trying to get him to react like he’s into her before she figures out it’s just wasting her time. This is a driving force behind the thing where the long time girlfriend begs and pleads with her boyfriend to marry her, but he’s “Just not interested in being married.” So eventually she splits from him and then within a year he’s getting married to his new girlfriend. Cue up, “He said he would never get married and now he’s getting married to someone else, why didn’t he marry me?!?!”