Yes, they feel "unloved". They can't even appreciate the attention they get.
I that would bother anyone, male or female. Your stronger folk will just move on, though. Why bother devoting energy to someone who clearly doesn't care to devote any of theirs to you?
All people are affected, regardless of gender.
Yes they do. I used to freak out at my boyfriend and think he would be cheating on me when he doesn't and get all moody and do weird ****. I hear dogs do that too.