Just One?

2 Kings 17: 35-36
"The LORD made a covenant with them and commanded them, 'You shall not fear other gods or bow yourselves to them or serve them or sacrifice to them, but you shall fear the LORD, who brought you out of the land of Egypt with great power and with an outstretched arm. You shall bow yourselves to Him, and to Him you will sacrifice.' "

So, I know the commandment about making God number one in my life. "You shall have no other gods before me", it says in Exodus 20, but here in Kings it's talking about having gods after God, also. But what does that matter? If I have God as my number one, how does looking to other things like money or other people secondarily change anything about our relationship?

hmmmm...

Well what if I was dating a guy, Steve. He was the most fantastic person I have ever met. He's kind, caring, and compassionate. He loves me in spite of my flaws, and isn't just trying to get in my pants. He's gone through every Aunt, Uncle, cousin, sibling, and parent just to get with me. He is my number 1 guy. But then, on the side, I Bob, whom I like to spend Thursday evenings with, because he's a good cook. Or on Saturdays, I like to cuddle up with Billy and watch the football game. BUT every other day of the week I'm Steve's girl. Clearly Steve is more important than Bob, and Billy combined, since he has 5 days, and they have 1 day each. 

Is that not still a cheating heart?

If this is wrong on the dating scene, how much worse is it in the spiritual realm where God has literally overcome all of heaven and hell just to be with someone as undeserving and wretched as I. And I'm wondering why I shouldn't have any gods after Him?
He's everything.