"Yishakeini minishikos pihu" - Kiss me with the kisses of your mouth - Shir Hashirim.
We want Hashem to kiss us. Beautiful! But why kissES - plural. Why isn't one enough?
There are two aspects of the relationship between husband and wife. 1] She is connected to him. 2] She is separated from any other man.
Imagine the scene: Chosson and Kallah in the yichud room. A man walks in and says, "Don't mind me. I will just sit here in the corner and read my newspaper." He sits down and begins humming to himself while reading about the latest "important" sports news. Not a good idea....
We are married to Hashem. It is inappropriate that anybody else should encroach on the relationship. If there is anything that comes between us, then the relationship is destined to fail...
There are two commandments: 1] I am Hashem, 2] Don't have other gods. Two aspects of the relationship.
I hope we all remain faithful.
[Based on R' Pinkus' sefer on Chinuch]