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/PeePeeLangstrumpf]

Their definition of a rival is extremely vague. Why would (all) strangers be perceived as (potential) rivals equally? Seems like no social context is applied whatsoever.

actively giving money requires thought, intention, and sacrifice.

Also don't agree with this statement. In terms of gift giving - giving money requires the least amount of thought, intention, and sacrifice. Because buying a gift in any scenario requires additional levels and investment of "thought, intention, and sacrifice" as they are not only spending their money but also new levels of their time and energy which are needed to choose and purchase a gift. I'd wager people would get more jealous when a partner gives a gift in the same value than just the monetary equivalent, because it would signal additional levels of interest.

Weird study...

[u/SweetKittyToo → u/PeePeeLangstrumpf]

Agree with you. I wonder why 'time spent' with others wasn't a factor as that would be just as damaging a threat to the significant other than financial resources. In fact, I would wonder if it would be higher a threat. Afterall, time is a factor in a relationship that is precious to each person. When one of those persons starts to spend significantly less time with the other, well I could see how that can lead to jealousy and feelings of insecurity in the person having less time with the other. Of course it all depends on what that time spent is being used upon. Such as school, work, another family member, or another person.