Tbh, many people feel a bit smug if someone who usually is doing better than them in life, has a setback because it just shows they're human not superhuman. But anyone often feeling happier by other people's misfortune has some deep seated insecurity issues. They are not happy with themselves in some way usually and haven't managed to realise their own fulfilment. People who are critical of others often use words they have heard used against themselves in the past maybe.

I would suggest that the spouse hasn't realised their true potential yet and needs encouragement to start filling their life with things they will get positive feedback from. If they feel good about themselves they won't need to fill the void by focusing on how other people are doing.