Anger is one of the secondary emotions. Usually something else is going on (we feel something valuable to us is, has been, could be taken from us and we go on high alert to marshal our forces to stop it, get it back, make sure we retain it/lodge a protest).

People think feeling anger is the expression of wanting to hit something/someone or other "violent" action (screaming/yelling) but that's not what it's for. It's a motivator so we enter into discussion with the "enemy" and ourselves and rally our forces, etc. :-)

You talk about being "so mad you wanted to hit something" but you do not mention what the problem was! It's the problem that has to be solved, not the feeling.

Feeling hurt is the base feeling; your estranged husband and his family are trying to take your daughter from you. How dare they????!!!! (that's the anger).

If you give yourself good self esteem, the anger becomes obvious and not a problem. Your daughter is yours too, your husband and especially your husband's family have no right to your "half" (at least) of your daughter. Your husband's family should get their ugly noses out of your business, too; that's an egregious boundary crossing into your and your husband's business. He may like it okay that they are in his but you don't want them in yours I don't think?

Usually all interpersonal problems contain some anger somewhere. Problems can be simple misunderstandings, and one needs to make sure that is what they are/are not first, before deciding on what actions to take to correct the problem. But the "Ouch! That's hurts!" that's our expression of anger. We start asking questions, "Why'd you do that? That hurt!" and hopefully they do the, "I'm so sorry! It was an accident, what can I do to help/make it up?" or, "It wasn't me, it was Henry over there" (and you go over and confront Henry).

Sometimes we get hurt and we try to blame others when we have allowed ourselves to get hurt or when the problem is ours, not the other person like we'd "like" it to be. Our feelings are ours, we are in charge of us and what we do about what we think and feel.

As with just about everything; we learn how to respond with/to our feelings as we are growing up; both by watching/experiencing those around us who care for us and by trying actions out ourselves and evaluating the response we get.

If Mommy yells when we get angry/frustrated at her, we might think the lesson is to not verbalize our anger or frustration; if Daddy handles our anger or frustration differently, we might learn to do things a couple of ways but think the lesson is about different people getting different treatment; we can verbalize our anger to Daddy but not to Mommy and we learn a false pattern for speaking our "truth" (only do it to people who are "nice"); as you see now, your husband and his family are not playing nice but you aren't standing up for yourself as an adult and looking for the resources and help to "make" them respect you.

Mostly it is about focus. You know how when you point, a cat will look at your finger? That is sort of what happens when someone says, "You hurt me!" Instead of looking at their hurt and how it happened/why they are hurting in their lives and how to correct things so they don't get hurt that way again, they focus on the other person, trying to get the other person to act in some way. Not happening. The other person can't know what will/will not hurt us/how we'll respond, is not in charge of how we feel, we are. They have their own hands full with their own emotions, thoughts, and actions. Everyone; good guys, bad guys, mediocre guys :-) scared and anxious guys, angry guys, you guys and me guys, everyone; wants what they individually want, not what someone else wants; you can't want what someone else wants, you can only want what you want and it is your job to figure out what that is and to try to get it.

Sometimes (often?) people want the same things and can work together and sometimes they want the same things (your daughter) and it's a "fight"/angry interaction. But unless you want to cry all the time, you have to decide you want to fight for your daughter, not let her just be taken from you and that requires thinking, planning, getting together a good legal team and others to help you so what you want isn't just "given" to someone else because you did not verbally express that want and follow your words/thinking/planning (part of verbal expression; you have to be able to articulate/state what you want before you can figure out how to work to get it).

Yes, pain requires tears but that's not all it requires. Just "giving up" doesn't help keep the pain away. You will keep getting hurt unless you do something to close up the problems causing the hurt.