Wiktionary
walk out on
vb. (context transitive English) to abandon or desert someone, especially a spouse
Usage examples of "walk out on".
I cant believe it, so I read it a fourth time, then walk out on her porch and sit down, dangling my legs in the air.
He was going to walk out on me and go live the last few days of his life with her.
Once or twice Raj thought he was actually going to walk out on the ceremony, and only a word from Suzette in his ear calmed him down a little.