Notice that this occurred when he was old and that his heart went not fully after the Lord. He did go after the Lord, but he did it in a haphazard way. To me, Solomon is perhaps the most vivid example of a Laodicean in the entirety of the Bible.
His downfall began (as we can see in the beginning of chapter 11) with laxity toward being careful about keeping God's commands regarding idolatry. Laxity is the first stage of lawlessness. The more lax he became, the more double-minded he became.
A double minded person loses his grip. Can you understand that? Just think of grasping something with your hand. If you're not really sure what you want to hang onto and your mind is playing back and forth between two different things, your grip is going to loosen on one or the other, because you're going to want to let go of the one and maybe get the other if you think maybe you have a better chance with the other. Your grip is going to loosen. I'm talking about a mental grip, but I think we get the idea.
Solomon gradually came to the place where he was not really hanging onto anything, but he was straddling between choices, gradually becoming more and more unstable, unsettled, and even deceitful until he became completely reintegrated into the world. He began to be moved almost entirely by human nature once again.
