Nikaah & Marriage Issues

Continuing a marriage if the mahr (dowry) has not been paid

Q: Is it permissible to continue a marriage if the mahr (dowry) has not been paid? 

I am currently married, but my husband has not yet paid the agreed-upon mahr (dowry). I would like to know if my marriage is still valid in Islam without the payment of mahr. What steps should be taken in such a situation? Is the marriage still considered valid, and what are the Islamic guidelines regarding mahr payments? Should I take any specific actions to address this issue?

Husband giving the false impression that he was not married when taking a second wife

Q: My husband didn't clarify about his previous marriage to me in our Nikaah certificate. He mentioned that he was divorced from his previous marriage but after our marriage he disclosed to me that his ex is still his wife and I am his second wife. 

My question is that, is our Nikaah done or because of his statement our Nikaah is not valid? Please clarify.

Husband spending time with his friends till late and neglecting his wife's rights

Q: I would like to know as a wife, whether it is a right of mine that my husband spends some quality time with me after work and Esha or is it just me being demanding and ungrateful which is how my husband sees it. Most nights he is at his friend's houses till 11 or 12 and then comes home when I'm already asleep after I've been waiting for him for hours. 

Anytime I bring up an issue, he tells me the hadeeth about the women being the greatest inhabitants of jahannam due to their ungratefulness and keeps saying it's in my nature as a woman. I need to know whether I am just being that type of woman and I just need to be fine with not seeing my husband and just be content that he sleeps next to me at night when he does come home.