..... After three washes the seams started separating and the fabric was falling apart....
Apparently you aren't supposed to wash them.
"The more specific guideline is to wash them once every 10 wears at most to keep them fitting correctly and make sure you minimize sagging."
How to wash and dry jeans - Denim Care Guide | Levi's® US
Discover the secrets to maintaining your beloved denim. Our comprehensive guide provides expert advice on washing, drying, and preserving jeans to ensure they retain their size, longevity, and style.