Japanese men asked what it is they feel most jealous about their girlfriends getting up to with other males supply an instructive list.
The ranking (with votes cast):
1. She hangs out with a guy without telling you (1922)
2. She gets up to a lot of skinship (1623)
3. The volume of her mails to him (1412)
4. They drop honorifics (1127)
5. She goes to him for advice (1031)
6. They often share the same topics of conversation (661)
7. She praises her male friends (549)
8. She’s cooler than you (539)
9. She’s smarter than you (90)
Fortunately the list runs out of steam there.
Unsurprisingly, it seems activities which are reminiscent of infidelity are the ones which cause the most concern.