Genesis 38 11-12a Judah then said to his daughter-in-law Tamar, "Live as a widow in your father's house until my son Shelah grows up." For he thought, "He may die too, just like his brothers." So Tamar went to live in her father's house. After a long time Judah's wife, the daughter of Shua, died.
So Judah is sending Tamar away - telling her to go back to her own house -' you know, just until my youngest son gets older to fulfill his duty.' And then the truth is told to us when the scripture says "he thought he may die too, just like his brothers". Judah had no intention of letting Shelah give Tamar a child. Here's where our foreshadowing from before comes in - He was lying about Shelah.
Tamar, who has been trusting this whole time - doing what she was told by these wicked men who were supposed to be raised by a man of God - went home to wait.
This would not have been a joy to her family. When she walked in the door - used and childless and widowed - surely her family must have been disappointed. "But wait", Tamar must've said, "It's only temporary until the youngest son is old enough". That false hope we put in people instead of trusting in God.
Then in verse 12 - the truth is told. Judah's wife dies 'after a long time' - long enough for Shelah to have grown up. I think this might be where Tamar gets the realization that Judah has no intention of fulfilling his promise. That Tamar would be childless and live in her father's house. This must have weighed on poor Tamar. What was she going to do? It had been years and now, there was not even a woman left in the house to care for the household - what was Judah waiting for??
What a feeling in the pit of our stomachs when we realize we have put our trust in the wrong thing. We have wasted time in stress and agony when we could've given it to God. But God is always watching and working . . . Even in Tamar's situation.