Honestly i do not feel you are being over protective or over emotional, the fact is she is amrried to you and in my own personal opinion a married woman has no buisness going to a "bar" with out her husband, to seek out attention and compliments from other men.
As for trust, trust is just not a given once we become married... we earned that trust from or S/O just like they earned ours, however, if we or they start behaving in ways that erode that trust, umm yea it can be lost.
The problem with the feeing that she can "go out and do whatever she wants. whenever she wants" is that she is married with children, and when that happened she, like you become responable for more that just your selves.
To be able to express yourself with out feeling guilty you need to know in your heart and mind that what you are feeling is not wrong and you are justified for expressing those feelings.
Knowing that is not going to make it easier to express them, however, you should not feel guilty for feeling the way you feel or expressing those feelings, because they are not wrong feelings they are hurtful feelings and you have every right to express that.
As for her calling you a "whiny baby" that is just one way of negating or shufling of the responsabilty of your hurt feelings by calling you names and such is is effectivly shuting you down so she does not have to "deal" with the hurt she is causing.
honestly it sounds like she is trying to live a single life, while being a married woman, it is hurtful and wrong.
She pretty much has been given a free pass to do what she wants, when she wants, and how she wants, and have a safe place to fall if things go bad for her, she does not have to work on her inner self confidence, self esteem, or marriage, simply because it is working for her, although it is not working for you.
know in your heart and mind that your feelings are justified and you have the right to express them, even if they make her uncomfortable. They probably will becauseshe probably knows already that what she is doing is hurting you and your family, but she is placing her needs and wants over everybody else's.
I really do hope things get better for you and your family, and that your wife can come to see that her behaviors are really causing pain and hurtand take steps to change that .
Tammy