Wife claiming that her first husband did not divorce her

Q: After married to a second husband for 20 years, the wife declares that she is no longer married to the 2nd husband because she was never divorced from the first. The 1st husband reclaims his wife. In the 1st marriage, no talaq was mentioned. The husband just stayed away from the husband. Is this allow in sharia and was the second marriage valid. What's the ruling on this?

Masturbation

Q: I am 21year old female. Please tell me if doing self pleasure is haraam in islam? If so then what are the physical effects of this habit? How can a female leave this habit?

Polygamy

Q: How does one view the issue of polygamy in the 21st century. What are certain advises given to someone who wishes to marry a second wife in these days without the support of the 1st wife and mother of the husband?

Husband not agreeing to live separately

Q: I live in a joint family. It makes a lot of problems for me. My husband is not agreeing to live separately. I have no issues with my mother in law she
also wants that like her two sons my husband also should live in a separate home but the main problem is my husband is not agreeing. I can't force him. I never fight or argue with him on any matter. Please tell me some wazifa to make my husband agree. I have four kids.