The Off-Limits Rule by Sarah Adams

Lucy Marshall has hit rock bottom. After failing to succeed as a single mom in Atlanta, she’s back home and moving in with her older brother, Drew. Reconnecting with her support system is the right thing to do, but Lucy can’t help but feel like a failure. Her four-year-old son deserves the world, and all she can give him is a spare bedroom. But Drew is the sweetest uncle, and some quality time might be exactly what they both need to start fresh. That is until she meets Cooper, her brother’s incredibly hot best friend.

When Drew senses something between the two of them, he puts his foot down on any shenanigans. According to him, Cooper is everything Lucy should stay away from: flirtatious, adventurous, and especially noncommittal. But Lucy has been getting the opposite impression so far; Cooper is a genuinely great guy, and she’s starting to catch real feelings.

Her whole life, Lucy has tried to do everything right, and look where that’s gotten her—so what if she were to try something wrong?