It's the same way one would endure death without dying, I suppose. What? Just stay with me on this.
Like marriage, divorce is a choice. It involves a rational process that's primarily informed by the emotional state. Consider this thought - we don't often remember the strict details of a trauma, but we overtly recall how it made us feel. Similarly, when we reach a point in a relationship where marriage is a consideration, this too is informed by how the whole arrangement, thus far, has made us feel.
The good side to being human: We feel. The bad side to being human: We Feel.
And sometimes we even feel the effect of the experience long before we actually have it. A surge of 'happy' chemicals fill our tanks as we anticipate that trip we've been longing to take. Those same chemicals take a dump as anxiety poisons us with presumptious thoughts of our partner leaving us. Anxiety dials '9-1-1' to fear; fear shows up, answering the call, because it assumes your life is danger. But it's not. In this case, fear is the firefighter showing up with no fire to fight. You claim you're burning, but you're not.
Fear is the creature response to our lives being threatened, to our mortal life ending. But it's a 'boy-who-cried-wolf' scenario. Fear shows up and there's no wolf. There's nothing to combat or ward off. Fear is wondering why you summoned it.
Fear shows up because despite living as long as you have, you've already experienced death - death in the form of RELATIONAL DEATH.
Divorce is the death of a relationship. What you're feeling, above shame or guilt or frustration or sadness, is GRIEF. Grief is loss. Grief is powerlessness. Grief is helplessness. Grief is always LESS. It's relational amputation and for some time you'll be walking around with a phantom limb. Two became one, then one became two.
Grief is good. Just because its property aims to make you feel "less", I suggest that it's actually making you "more". And by more, I mean to say that it seeks to reveal the deeper parts of your self. Knowing yourself requires that you know what pleases you as well as what scares the shit out of you. But you decide to let it be your guide. You own it. It works for you, so let it do its job.
Just like in life, we have funerals that function as homage and closure. Have you had your emotional funeral yet? Have you accepted that it's over? You need to. You need to grow. And growth means that you endure.