In Good Company (2004) on Netflix

Dan Foreman is headed for a shakeup. He is demoted from head of ad sales for a major magazine when the company he works for is acquired in a corporate takeover. His new boss, Carter Duryea, is half his age--a business school prodigy who preaches corporate synergy. While Dan develops clients through handshake deals and relationships, Carter cross-promotes the magazine with the cell phone division and Krispity Krunch, an indeterminate snack food under the same corporate umbrella. Both men are going through turmoil at home. Dan has two daughters, Alex, age 18, and Jana, age 16, and is shocked when his wife tells him she's pregnant with a new child. Carter, in the meanwhile, is dumped by his wife of seven months just as he gets his promotion. Dan and Carter's uneasy friendship is thrown into jeopardy when Carter falls for, and begins an affair with, Dan's daughter Alex.