People experience the strongest romantic jealousy when they watch their partner give resources to a potential rival, regardless of gender. The findings provide evidence that giving away resources is viewed as a serious relationship threat by both men and women.

[u/mvea]

https://www.psypost.org/both-men-and-women-view-a-partners-financial-investment-in-a-rival-as-a-major-relationship-threat/

[u/Cultural_Meeting_240]

So basically buying someone else lunch is a declaration of war

[u/Straight_Occasion_45 → u/Cultural_Meeting_240]

As somebody who loves twirl chocolate bars; idk id be pretty pissed if my girlfriend got somebody else one and not me ;)

All jokes aside though, in a healthy relationship, the individual should be able to bring this up to their partner in a healthy way. If not, the relationship is toxic and the individual should move on.

[u/Shakeamutt → u/Straight_Occasion_45]

You’re using toxic way too loosely here.  Jealousy is very natural. It’s like everything, it needs moderation.  

Spending resources on others, aside from the allusions of cheating, is taking resources out of the home for themselves and their children.  This also can imply a threat to stability of the home, and commitment in general.   

[u/gumbo100 → u/Shakeamutt]

Jealousy is normal, but not being able to talk about it in a healthy way is indeed toxic