Marital problems

Q:

1. If a husband promises his wife that he wont ever want to take another wife/wives, does he forego his right? What happens if he breaks the promise and he does a second nikaah?

2. If the first wife cant cope or bear the pain of it, can she leave him?

3. If he feels that the second nikkah was a mistake and he regrets it, can he leave her? Both wives are living in 2 different countries. He doesn't spend equal time nor equal money on both his wives. He really loves the first wife more than the second and both the wives are aware of that.

4. Also, if the husband refuses a divorce, can the wife request a khula'?

5. If yes, does it mean that the kids have to go to their father and if the husbamd demands any amount of money he wishes too, she would have to pay in order for him to agree to khula'? 

Wearing the latest style abaayas and niqaabs

Q: Im 24 years old. I cover my face with niqaab. That means I wear abaya and cover my face when I go out. I use a normal, usual and black face cover to cover my face which is in abaya shops. Usually I wear the latest design abayas but it does not fit and it doesn't show my body's shape but it's the trend. So I had an idea to change my face cover material that still covers my face fully. Is it permissible to wear a different kind of face cover or it musn't change. That means, the materials and the colours of face coverl, can they change? There are abayas in may kinds of materials, so like that can I use different material for face covers?