I am jealous but embarrassed to tell my spouse for fear of being seen as oversensitive. What should I do?

Bottling up jealousy out of embarrassment is more dangerous than expressing it well, because it will come out as sarcasm or sulking. Speaking up is not a sign of weakness; it is a sign you want this relationship to be honest. Choose a calm time and start with ‘I feel’, not with an accusation. For example: ‘I feel uneasy seeing such a close relationship with them. Can we talk?’ Explain your feelings rather than demanding control. A loving spouse will appreciate your honesty. If you find it hard to speak, try writing it down first. Small openness builds great trust. See communication & emotions.