Had my cockapoo at the vets today, surgery for undescended testicles. Long story short they cut him open couldn't find them, then his heart rate crashed and apparently we were very close to losing him

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I'm thankful he is home and recovering but now I have several problems. I am £500 worse off and my dog still has testes (somewhere). After recovery they are recommending an MRI at £2.5k (not covered by insurance) But in reality the problem is I don't want to have him put under again after today. I'm tempted to leave him be. Is that selfish?.