It Gets Easier by Justine Avery

Jake's loved and lost, suffered failed relationships and felt real sorrow, but the new girl in his life may just be the one to finally put an end to that life.
His girlfriend Samantha is sweet and kind, full of joy, and the kind of girl Jake can be perfectly content sitting in complete silence with. It's so comfortable, so easy, to fall completely for her. In fact, Jake would doanythingfor Samantha, anything at all.
Just returned from attending Samantha's family reunion, Jake's high as a kite, basking in the realization that he's been officially accepted as one of the family. He can't believe his luck, especially as he's driving off into the sunset with Samantha herself and so looking forward to those precious, anticipated moments alone with her. What could possibly go wrong?
Thump thumpresonates from the trunk of the car as they speed along the highway together.
Thump thump.
He falls head over heels for her... but not exactly in the way he intended.