Question Summary:
Was my Nikāh valid?

Question Detail:

I was happily married few years ago and I loved him and got married we had a child together in ----. I got into sin and started sinning, listening to music ect and fell into zina with another man. May allah forgive me. I told my husband of this he was very angry and upset and cried but didn't want to lose his family. I wanted a divorce of him and then he did give me the divorce. only THEN did i realize how much of a stupid mistake I made and highly regretted it. This other man, I told him I didn't love him but i did like him. He said to me, marry me and things will get better I really wanted to get married back to my ex husband but after three separate divorces you cannot until you genuinely marry another man and it doesn't work out.
 
Anyway, this man close to getting married told me I have spent the money I saved to get a house, on a car and if you still want to get married you have to wait for a year at your parents but we can get married and see each other still. So i agreed. I knew I had to get married to someone even if i wanted to ever get back with my ex. I knew i had feelings for this man and I knew him for a year and was close to him so I thought yes I will marry him and if it doesn't work I can remarry my ex. On the day of divorce I didn't feel that I was faking the nikkah in fact I cried thinking subhanallah i'm married now.
 
after a few weeks, I went through his phone and saw that all that time we was with me before marriage and telling me to get a divorce from my ex, he was talking to other women saying he wants to sleep with them, talking to a girl on facebook telling her private details about me and him and after that, i also found on his history we was watching porn EVERYDAY or every other day when he was with me also a night before he married me. I lost all trust and couldn't believe it and asked him for a divorce.My ex want's to take us back, he has never ever talked to another girl in this way the four years I was with him, he is very practicing as he accepted islam few years back and since then he has prayed and followed islam more than i have. 
 
Now shaytaan is putting in my mind that my marriage wasn't valid with him because I only did it to get back with my ex  why do I keep thinking this.Would you say my nikkah is valid with this man.
Could I do istikhara and ask if my marriage is valid im so confused.

Answer :

In the Name of Allah, the Most Gracious, the Most Merciful.
As-salāmu ‘alaykum wa-rahmatullāhi wa-barakātuh.
If your second husband divorces you after consummating the marriage, you may remarry your first husband after the expiry of the ‘Iddat (waiting period). [1] Your marriage with your second husband is valid and will be considered a valid Halālah. [2]
Sister, we hope you realized the negative consequences of sin and the wrath of Allah in committing sin. It is sad that you only realized the unfaithfulness of your second husband after you married him and not when you were in an immoral relationship with him. Remember, when a person does not fear Allah, he cannot be trusted. Seek Allah’s forgiveness by making sincere Tawbah as Allah is Most Forgiving. Change your life and gain closeness to Allah.
 
And Allah Ta’āla Knows Best
Muntasir Zaman
Student Darul Iftaa
USA
Checked and Approved by,
Mufti Ebrahim Desai.