Jealousy: Most commonly, this word is applied to a person who knows their man/woman is cheating on them and is upset about it to the point where they nag and cry incessantly. Also, perhaps a friend is hanging out with new friends and is ignoring their old friend. It has also been used as a replacement for envy. Conversely, "I'm not jealous," means "Go ahead and cheat on me or leave me in the lurch. You can't hurt me."
Wrong. Jealousy means cheating or betrayal is suspected, but with no proof or basis. With no proof at hand, one still behaves as though it's actually happening and cries at, clings to and berates their better half. Or perhaps they're involved with someone who is seeing other someones because no firm commitment has been made. Jealousy is not about the shape of the relationship, it's about the insecurity of the people in it.
Envy: Someone wants what someone else has, or resents them for having it. "I wish my man were like hers." "He has a nice car. Why don't I?" Not quite a replacement for hater, but close.
Hater: One who randomly dislikes someone else for what they have. "That bitch has a nice car. She doesn't deserve it." "He has a fine woman. I'd treat her better."
Betrayal: The cheating and lying and verbal unkindness has happened. One has been abandoned or emotionally harmed in some way. This is the real deal. It often leads to feeling disrespected, and rightly so. The one who has been betrayed is sometimes accused of being envious or being a hater because of how they react to pain and rejection, but a bit of backlash is normal.
Disrespected/lack of respect: Asking for respect is pointless. One either deserves it or they don't. Being disrespected means someone is doing something to or at someone else that they know would hurt. When ones partner cheats and knows how much it would hurt their man or woman, they are combining betrayal with lack of respect. This concept can also be applied to a myriad of other types of relationships, such as a friend talking smack about another friend behind their back.
Off you go to agonize about your imperfect relationships in a more accurate way.