LW1 let me give you a clue as to why she doesn't want to 'hook' up anymore.
"or if my feelings for her are just lust over how good the sex was."
"I’M WORRIED that the only reason I do these things is a secret desire to try to get into her pants again." 
"I don’t want to lead her on under false pretenses,"
Said no real guy ever...unless he was saying them to her as a false pretense to get into her pants.
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She's in her mid-40s she's done with boys, particularly the emasculated type.
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P.S. Once you are in your mid to late 30s, stop saying "hooked up".