Writing a talaaq in the presence of the wife

Q: I just would like to know as I was in contact with another woman not physical but via social media. My wife forced me to write down my 3rd and final talaaq to her and made me leave my home. I would like to know if this is valid as I had no intention of leaving her as I loved her. I married her with two kids from her previous marriage and we were a happy family but I let an intruder into my life and messed my marriage up. Do I have a right in this matter?

Lengthening the beard and trimming the moustache

Q: In the Hadith a command is given to lengthen the beard and trim the moustache. I know that it is waajib to lengthen the beard, but what about the moustache? Is shortening the moustache also waajib? If not, then people argue and say that if you say that lengthening the beard is waajib, then trimming the moustache should also be waajib because they in the same Hadith.

Mistake in Attahiyyaat and Durood-e-Ebrahim

Q:

1. If one happens to omits portion of Durood Ibraaheem due to one forgetting it or making a mistake, is the Salaah valid?

2. If one happens to recite Tashahud and one repeats the portion( Ash Hadu...) where the index finger should be raised, perhaps due to getting stuck, should one raised the finger twice?

3. If yes, and it was not raised twice, is the Salaah valid?

4. Whilst in Salaah, during Durood Ibraaheem, one adds the words "Sayyidina" before the words and Names Muhammed (Sallallahu Alaihi Wassallam) and Ibraaheem (Alayhis Salaam), is the Salaah valid?

Mocking and ridiculing people

Q: Person A tells Person B the following joke. He says the memon was in Jahannam when he met his friend. His friend said to him that you were so pious, how did you end up here? The memon replied that I have a place in Jannah, but I put my house in Jannah on rent. Person B laughed at the joke. I am aware that in Surah Tauba that there is a verse which speaks about joking about Allah and his signs and this leading one to come out of the fold of Islaam. In the scenario presented above, do both A and B lose their Imaan and in the process invalidate their Nikah?

Fulfilling the obligation one owes towards one's mother and wife

Q: I am the only child of my mother, married with two kids alhamdulillah. But recently things are not going well for me. I'm not in a position to provide for my mother and wife at the same time and this is eating me up. I understand very well both have rights upon me but my earnings are very little! It's like choosing my wife over my mother.