I Kings 3:2 Only the people sacrificed in high places, because there was no house built unto the name of the Lord, until those days.
Solomon loved God but he also tolerated and later participated in the worship of others. Probably his heart was for God, Jehovah, but his policies opened the door for the worship of false gods.
God wants, expects, and demands all of our worship. He fully thinks that He is the only God. He wants to be treated as such.
Today, we do not have much use for other gods, but money, power, and popularity can become way too important to us.
We will not stand for God because we do not want to lose the things that we like. We have become tolerant of the LIE.
There is only one God and He is Jehovah God. You must come to Him through His Son, Jesus!