Weakening of the ligaments unavoidably leads to deformation of the spinal column. In other words, don't do relaxed stretches for forward flexion of your spine or toe touching. A suspended side split, like a fire walk, is an act of faith. This is not psychobabble, this is a fact. There is an intimate connection between the limbic system, which governs the emotions, and the neural networks that govern muscular length and tension.
Scientific studies show that fear and anxiety, as well as pain, reduce flexibility.
With that in mind, maximize the safety of your stretches-and their perceived safety. If it takes three chairs, a step stool, and a spotter to make you feel safe during your splits-so be it. The reasons for your fear may not be real, but it wipes out your flexibility for real just the same. If you do not believe that you can do a wishbone, you never will. And vice versa.