I agree with Paddington, also its a bit harsh to dump her for being a bad lover that's willing to improve, (by reading books, watching videos, researching talking to her gf's, talking to you etc) its not so harsh to dump her for being a bad lover that doesn't care, infact id say people that don't care deserve to be dumped.

Don't train her up tell her to improve give her a time frame to improve and if she doesn't fire her