Tilly just wants to escape everything, family, friends, men. Her life had become an ongoing reminder of what she had lost, and the only way to escape the pain was to book a ticket and get out of the country. Maybe when she returned she could start over, rather than living this shell of a life, that was if she even came back.
Ben and his twin had been blissfully unaffected by Fenrir females when they entered their heats, if either of them were acting like clowns it was always because they chose to, unlike the males in their den who were complete idiots any time a potential mate was around. Ben had always assumed he would get a mate eventually, but with his siblings seeming to find their mates one after the other it was becoming more and more likely.
When Ben meets Tilly he knows instantly that she is his mate, the only problem is, not only is she human, she's already had a mate and has lost him. Ben wants Tilly, but Fenrir mate for life, so if her broken heart leads to her rejecting him he may find himself without a mate forever.