I'll try to answer your questions but bare in mind, I'm still a teenager so my answers may not reflect those of older men who you may wish to have answered.

The simple answer is that when we're upset, we're usually not very rational and we regress to a more primitive state where if something is near-by, we're going to blame it. Also, we're more likely to not blame ourselves for the reason due to fundamental attribution biases. When I say "we", I mean males and females because this applies to both.

I cant answer this one personally because I don't care if they look exactly like a model but for the ones that do, they probably like the model and want to have a person that looks like that model so they can fulfill their sexual desires and gratification.

I think this is for men or for couples who are more insecure and controlling or jealous because they think their partner may be hiding something or be cheating on them or saying something bad about them or stealing from them and so forth. It's a long list of possibilities.

Possibly because the man is insecure and unsure if the partner will leave him. Also, they may love the partner immensely and feel that her friends are intruding on his "space" with her even though they're not. It's akin to when a mother has a baby and spends time with it and less time with her loving husband. The husband may feel jealous and that the baby is stealing his wife away from him.