she had only been with her ex before me and it had never been an enjoyable thing for her, so she was happy to leave it undone

Alpha widow red flag right there.

The "not enjoyable" comment is a kafkatrap. If the betabux passively implies he wants to fuck and is persistent, she guilts him by saying he is pressuring her and that gives her hamster a validation for dumping him. And he if he is so thirsty he backs off to "give her time" and doesn't try to fuck her then that's her permission to fuck around because he "isn't interested".