Iddat period of talaaq

Q: I am 47 years old and married for 19 years. This is my third marriage (I am the only wife). I was married twice in my twenty's and got fasagh for both (valid reasons). The problem is at that stage of my life I had no guidance from anyone. I have a father and a brother but they never explained to me right and wrong, the only Islamic thing my father spoke to me about was to wear a scarf and I thought that makes you a Muslim. My mother is a revert and my father and brother also never guided her. I never made ibadah, never knew much about the deen as my father also didn't live and practise deen. Now I am coming back to my actual dilemma. Alhamdulillah I have transformed tremendously since I married my current husband of 19 years and he has been my guide my anchor. I am really living and fulfilling my Deen. There was a topic the other day about iddah and the explanation about the punishment of not observing idaah properly. Therefore I need advise. For both marriages I never observed iddah because of ignorance, no one explained it and maybe they did and I didn't understand. I now want to make things right but I need guidance. Please give me advise on this matter.

Issuing a divorce via a text message

Q: I was made to marry as soon as I turned 18 and even though I refused my family still went ahead with it. I tried my level best to make something I never wanted to work but instead gained nothing but abuse from the person I married. I received a text from him saying he is divorcing me. When asked about this he said he was joking and never really meant it however I am now wanting a divorce. My family are not agreeing to it yet I wish to go ahead and get one. As I am not registered married in the UK I don't have the legal side of paper work for the divorce to worry about. Will you just let me know how to go about my divorce the Islamic way and  if there is any paper work or form for divorce in Islam?

Will one become a kaafir if he does not perform Salaah?

Q: The Prophet (Sallallahu Alayhi Wasallam) once said, that the one who leaves or abandons prayer is a kaafir. So what if one who has parents that are from a Muslim background, (practising or otherwise), has never prayed the 5 prayers out of laziness or other reasons, but believes in Allah and His Messenger; is he/she still considered a kaafir? I mean, will they still be Muslims, but only called non-practising Muslims due to them not praying? Also, what if they try to pray sporadically, but without wudu or without saying the prayer words properly or without intention, only to please others (while they still know this is wrong); are these people still considered non-practising Muslims, even though they still believe wholly in Allah and His Messenger? How is a Muslim defined in this case? The reason why I am asking this, is because I heard that because one has either left the prayer or has never properly prayed to begin with, is not even considered a Muslim, regardless of whether he/she believes in Allah and His Messenger or not?  Is this correct?