I liked this movie more than I expected to. The story stayed with me long after I'd watched it as I found the characters to be very authentic, and the casting and portrayals were very good. The movie doesn't condone, justify, or glamorize extramarital affairs. In fact,it reveals how something that might, at first, seem like just a casual and temporary dalliance can snowball into lasting negative consequences for everyone involved. When the affair begins, I was thinking she should have stopped it right at the first kiss, but then... there wouldn't be a movie.
As Ellen's feelings for young Travis strengthen, she becomes torn up over her betrayal to her husband, who is nearly 20 years older than her. The affair brings up negative emotions that she'd probably been suppressing for quite a while, although she truly cares for her husband and the life they've created together. These conflicting emotions help explain how it was relatively easy for her to begin the affair with Travis in the first place.
The ending also seems realistic and appropriate, not fully resolving what happened, but highlighting how the characters' lives have significantly changed.