Maybe in Missoula by Toni Volk

From her hometown of Butte, Montana where she grew up in the local bar her parents own, she takes her teenage son and heads for Idaho. But something stops her. Bound to the big skies and the crisp scent of the pines, they end up in Missoula, where Annie reconnects with her husband's brother Paul, her first love. There she examines her life - her passionate attachment to these two brothers, always in competition with each other and for Annie's affections.