Any time you make a sort of catastrophic prediction, (for example, 'I could never cope if my spouse left me') try to think of less catastrophic ways of phrasing the situation. For example, 'If my spouse left me, I would have to learn to socialize better and cook, because my spouse does that for me now'. From there, you can look on the bright side of the challenge, you will learn to cook and socialize, thereby making you a more independent person. The spouse leaving you would still hurt a lot, but your mindset will have changed from an unproductive one to a productive one.
Every loss you face is a chance to learn more and improve yourself.