Question Summary:
Should I marry the woman I committed adultery with and to whom will the child be attributed?

Question Detail:

 Dear Imam, before asking my question, I want to say that it is very sensitive situation, and nowhere I could not find a similar question. And I hope to hear the wisdom in your answer, and the answer without bias. I need help very much, and am going to be guided by your answer and do what you advise me.
Im a muslim since coming to this world. And thank God for that. However, began to practice Islam in my 21, and began to perform the prayer. Up to this point made a lot of mistakes and sins. A Muslim can not talk about their sins, but I do not know what I do now, so I ask you.I met a girl. She was married and that time and she had 1 child. I found out about it only after 2 months. But at that time, she was already pregnant. This girl told me that the baby from me. I just left, I had disappeared after that. 3 years have passed, I saw a photo of the child, and it looks like she was not lying, I'm sure 99%.
But I was tormented conscience, found a hadith which states that the child belongs to the mother of adultery, and for father nothing. And thought that it is necessary to forget about her. Recently realized that we should not run away from liability ... But no matter how much good I did, I do not think I have redeemed before Allah. There is no good in my act that would cover this my mistake, this darkness.
I'm not married, and she said that she divorced recently. But on her social page still photos with her husband. I am the only child in the house. And all my friends know about her, what did she do, I'm afraid if I take her as my wife, I can not trust her. I'm afraid that my friends will look askance at her. And my relatives if they figure out that she was married and that she had 2 children, I Do not know how they will react. And if they see a second child, and find that she looks like me? Then goodbye my instruction, who will listen to me? And this is the man who told us to afraid of Allah ?! I'm confused. I'm sorry that such a long question but face to face none of the Imam is not about to ask.

Answer :

In the Name of Allah, the Most Gracious, the Most Merciful.
As-salāmu ‘alaykum wa-rahmatullāhi wa-barakātuh.
Allah is the Most-Forgiving, the Most-Merciful and His Forgiveness and Mercy is greater than our sins. It is our duty and obligation to repent for our sins with remorse and to firmly resolve to never commit that sin again.
Whenever you get this thought that no matter however much good you do or no matter how many times you ask for forgiveness it cannot make up for that sin, raise your hands and make the following duā three times keeping in mind its meaning [i]:
اللَّهُمَّ مَغْفِرَتُكَ أَوْسَعُ مِنْ ذُنُوبِي وَرَحمَتُكَ أَرْجَى عِنْدِي مِنْ عَمَلِي
“O Allah, Your Forgiveness is wider than my sins and
I have more hope in Your Mercy than in my own deeds.”
Getting married is a major decision and you need to take into account all the relevant issues particular to her case. You have stated that if you marry her you cannot trust her and that you did not even know that she was married at the time you had a relationship with her. If you do marry her you will constantly be thinking whether she is hiding anything from you just as she hid from her previous husband and going into marriage with these thoughts will only cause distrust and enmity between you two. In addition, you need to stop looking at her photos and stop talking to her as she is a complete stranger to you.
As for the lineage of the child, it will not be attributed to you. Since the woman was married at the time of committing zinā, the child's lineage will be established to the woman's husband unless the latter made a li'ān (allegation of adultery). [ii] [iii] [iv]
And Allah Ta’āla Knows Best
Sohail ibn Arif,
Student Darul Iftaa
Chicago, USA
Checked and Approved by,
Mufti Ebrahim Desai.
 
حدثنا إسماعيل بن محمد بن الفضل الشعراني ثنا جدي أنبأ إبراهيم بن المنذر الحزامي ثنا عبيد الله بن محمد [i]
 بن حنين حدثني عبيد الله بن محمد بن جابر بن عبد الله عن أبيه عن جده قال : جاء رجل إلى رسول الله صلى الله عليه و سلم فقال : واذنوباه واذنوباه فقال هذا القول مرتين أو ثلاثا فقال له رسول الله صلى الله عليه و سلم : قل اللهم مغفرتك أوسع من ذنوبي و رحمتك أرجى عندي من عملي فقالها ثم قال : عد فعاد ثم قال : عد فعاد فقال : قم فقد غفر الله لك
حديث رواته عن آخرهم مدنيون ممن لا يعرف واحد منهم بجرح و لم يخرجاه
المستدرك على الصحيحين، ١/ ٧٢٨
ومنها ثبوت النسب، وإن كان ذلك حكم الدخول حقيقة لكن سببه الظاهر هو النكاح لكون [ii]
 الدخول أمرا باطنا، فيقام النكاح مقامه في إثبات النسب، ولهذا قال النبي: - صلى الله عليه وسلم - «الولد
  للفراش، وللعاهر الحجر» وكذا لو تزوج المشرقي بمغربية، فجاءت بولد يثبت النسب، وإن لم يوجد الدخول
  حقيقة لوجود سببه، وهو النكاح.
  بدائع الصنائع، ٢/ ٣٣١ - ٣٣٢
فتاوى محمودية، ١٣/ ٥٣٣- ٥٣٤ و ٥٤٥ - ٥٤٦ جامعة فاروقية [iii]
قال أصحابنا: لثبوت النسب ثلاث مراتب (الأولى) النكاح الصحيح وما هو في معناه من النكاح [iv]
 الفاسد: والحكم فيه أنه يثبت النسب من غير عودة ولا ينتفي بمجرد النفي وإنما ينتفي باللعان، فإن كانا ممن لا
 لعان بينهما لا ينتفي نسب الولد كذا في المحيط
الفتاوى الهندية، ١/ ٥٣٦