Live, Love, Spy by Lexi Blake

Life can often be awkward when you’re a child genius. For Louisa Ward, that came in the form of meeting her one true love at the age of 12. TJ Taggart was perfect. But being a year younger and a full grade ahead of him in school always made things weird. Working in the CIA has turned her into a strong and capable woman. Until TJ walks into a room. Fifteen years later, she still gets butterflies every time she sees the gorgeous soldier, but she’s tired of waiting and ready to find love, even if it can’t be with him.
TJ Taggart always knew he wanted to be a soldier. But joining the Army would require a sacrifice. Since meeting Louisa, TJ knew she was the one for him, but they had different paths in life. Lou was meant to change the world at some prestigious research job or maybe teach at an Ivy League school. There would be a chance to sweep her off her feet when his time in this dangerous life was done, and their happily ever after could begin.
Before he can make it home on his latest leave, TJ is kidnapped by an unknown adversary. As he waits to die, all he can think of is the time he wasted and how badly he wants to be with Lou. He’s more than a little surprised when his sweet, quiet girl shows up leading a CIA special ops squad to bust him out. Back in Dallas, it’s time to claim the woman of his dreams. He has a plan to win her over, until the adversary who almost killed him returns to finish the job.