Question Summary:
Can I go back to my first husband after three divorces if I had intention of halālah with second husband?

Question Detail:

I am in need of help from yourself. Please be aware, I know of the rule that if a man divorces his wife three separate occasions she is not halal for him until she genuinely marries someone else and it does not work out) I got married to my ex husband in----- we had a child in -----. I was very much in love with him, he prayed and still prays 5 times a day since he reverted in ---- and is very very in deen since) shaytaan took over me and I stopped my salah and started sinning, I met another guy and then I asked my husband for divorce (I am aware of what I have done and ask allah for forgiveness and how shameful this is I understand).
 
After the divorce (3 divorces, three separate occasions), I regretted is SO much and just wanted to get back with him. However, I was with this guy and told him I dot no love you and he said it does not matter, we will get married and things will get better. He knew I did not love him, I did have feelings for him and liked him a lot as we were very close and talked everyday all day.
 
Before I got married to him, it was in my mind that most likely it will not work out and I want to get back with my ex husband but I did not fake the nikkah because on the day of nikkah I cried and though wow i' married and never had a doubt about my nikkah and me and him always spoke and said '' This isn't sin anymore '' maybe at the back of my mind it was the fact I want to still get married to my ex A few weeks after, I saw texts and this man talking to other girls and saying rude things that he wants to sleep with them and I thought he was completely someone differen. I asked him for a divorce and he gave me the divorce yesterday.
I have done istikhara asking is my nikkah valid or not and sheikhs told me to ignore the dreams and the only STRONG feeling I got from istikhara was that It was not valid (but at the same time I got answers from some scholars/mufti like shaikh hasan ali, kamal el mekki, Yusuf Lehar, Mufti Hussain Kamani and a scholar from greenlane masjid from Birmingham UK and they had all told me it is valid.
 
I am still not convinced because i Have read online that any intention of marrying your ex whilst your marrying your current husband your nikkah will be invalid. At the nikkah there was my dad, the groom, two male witnesses from his side and the imaam please refer me if you can help but I would really appreciate it if you could help. Is my nikkah valid.
Please keep in mind that when my nikkah was done it didn't even exist I'm his mind that he's doing this to make me halal for my ex he genuinely loved me he said

Answer :

In the Name of Allah, the Most Gracious, the Most Merciful.
As-salāmu ‘alaykum wa rahmatullāhi wa barakātuh.
According to our understanding of your query, you married your first husband in 2009 and he issued you three divorces in 2011, after which you married your second husband. Your second husband then divorced you and now you wish to remarry your first husband.
If this is correct, the restriction of marrying your first husband has now been lifted, and you may remarry your first husband once your ‘iddah is complete, on condition that you had consummated the marriage with your second husband.[1]
Although to marry a second husband with the intention of making the first halāl is undesirable, the marriage will be valid and the woman will become halāl for the first husband, as long as the intention was not verbalised and stipulated as a condition in the contract of marriage.[2]
And Allah Ta‘ālā Knows Best 
Zameelur Rahman
Student Darul Iftaa
UK
Checked and Approved by,
Mufti Ebrahim Desai.
www.daruliftaa.net