The Parcel by Leigh Suznovich

Lyra Spinelli is trying to put her life back together after her marriage suddenly comes crashing down. Her trust is shot, her already high walls are firmly in place, and she is focused on work. Growing up and living with a rare genetic disorder has made her wonder whether she is even made for a healthy relationship. The last thing she needs is an attraction to the charming UPS driver Taran, no matter how much she is drawn to him. The more she interacts with him though, the more impossible he becomes to resist.
Taran Malloy hasn’t had much room in his life for romance, working long hours and taking care of his widowed mother. After meeting Lyra though, long forgotten feelings bubble up and he sets his sights on getting to know her and her story. As he slowly unravels her many layers, he finds the woman of his dreams. When Lyra has to overcome her biggest medical hurdle to date, he hopes delivering his growing love for her will be enough to make her stay.