Rancher’s Little Lover by Jordan Silver

Hawke Jameson is a thirty-six-year-old single father. When his son Garrett comes home for a visit from college bringing some new friends along, one of them is the outspoken Lynette. One look at the young beauty and something deep and forbidden unfurls in his gut. He tells himself no way hands off; she’s too young. But then he catches her scent, the one a woman gives off when she senses her mate, and all bets are off.

“I want to have you in the worst way, Kitten. But if we do this there has to be more to us than just sex. There’re going to be rules.”
“What kind of rules?”

“I won’t share you; that’s first and foremost. If I take you, you’re mine no questions. I haven’t felt this way about anyone in a long time. In fact, the last time I felt anything like this it wasn’t this strong. You have to be very sure before you say yes, because baby if I put you under me when I put you under me, there will be no turning back.”