Please help. Do I Walk Away? ?

I am a new muslima in much turmoil about 2 make 1 of the biggest decisions of my life. 2yrs ago before my conversion I met a man. Instantly & uncharictaristically on our 1st meeting a warm wave went thro my entire body I cant describe & the strongest feeling of knowing & belonging came 2me. A previously sensible 33 yr old career woman this was quiete out of character. I went home & told friends, I new I had just met my husband. He would talk to me of Islam & pray & i felt so drawn 2 God again in all the happiness he brought 2my life, I began prayer again & being around him made me want 2 become a better person & I was so aware & thankful 2 God 4 my blessings. I used 2 ask God 4 an opening in marriage 2 this man.He is muslima & I was Catholic. After 1yr of spending time & learning from this man I got the worst shock in my life.A call from a woman who claimed 2b his wife with children. It was 2 test me & my faith & morals 2my core. I felt my love 4 this man was so strong, like it was destined 4 me or decided 4 me like b4 I was born. But I had 2let go of it, giving bk all I knew as right 4 the sake of doing right. He explained he had not been honest for fear of losing me, as he knew morally I would walk away. He explained married as teen & long term regret. Many yrs unhappy but found love of his life in me & also felt feelings of being thankful 2 God & wanting 2b become better muslim. Explained wife was christain & kids raised as christian & many marital problems, lft many times b4 meeting me. Broke my heart 2 let him go. But I continued regardless with my feelings of being drawn back 2 God & in my darkest months stayed at the mosque, submerged myself in reading & began 2 take refuge & feel slight ease from my constant inside turmoil of heartache, like half my soul was missing. Months on, subhannallah... I converted 2 Islam - alone with no family support - all english catholic family. & began rebuilding my life which feels like in a million pieces knowing I can never be with this brother, who I love with all my soul. Months later out of the blue, his family member calls & explains the brother has asked her 2 act as maharam & requests I come to family eid celebration & in my best interests 2 attend. He proposed . Explaining lost his soul when lost me & wants halal life with islamic wife &ready 2 change his life for hajj & marriage etc.. The family & imam have given their fullest blessing. This is such a blessing 4me, as I love him with my entire being, & also means I now have path of islamic marriage in a life where I know few muslims and have no wali etc... and my family will disown me on my conversion. He also vows to help teach myson Islam. For me... this is all my prayers answered from Allah. But inside I am torn at hurting another himan being. The 1st wife. On proposing he explained he was divorcing his christian wife - they have been seperated for 1yr. But he hasnt, & we due 2b married in few wks. Bigamy... in this country but islamically valid marriage. He now says he not ready 2 divorce but still wants islamic marriage without taking 1st wife consent. Fears she will not allow him to visit his children. I truly love this brother as only Allah knows, & he comes with islamic family in full support for me & path to submerge myself in islamic life. Without him I feel dead inside like he is the other half of me & i have asked Allah for this so much. I am so confused now, as he did not get divorce that there may be hope for there marriage and am coming between that. He will not discuss it. Says it has nothing to do with our marriage & he will never go back to 1st wife but now unlikely 2 divorce her. I am torn if Allah is answering all my prayers in this marraige or testing me as it feels deceitful that the marriage will take place without 1st wifes knowledge. & she also loves him. I fear what will happen to me & my son with no islamic friends or family without this marriage apart from the fact that I love him so much & he claims the same. For me the marriage will bring everything, but for the 1st wife... I feel I am doing her wrong. I am not sure if to give up everything Allah has offered to me , my whole world for the sake of this women. As maybe Allah is testing me in not breaking family ties... or if to be so greatful to Allah in the path he is offering me, that I have prayed for, longed for and can benefit this man in his deen, my deen and my son's deen. Please can someone offer me guidance. I am so confused muslima.