Answer
Salam (Peace) Mariam,
Thank you for contacting About Islam with your question.
I have read your question carefully and I would like to thank you for many things: first for your concern not to have any illegal relations with a Muslim man; second for your feelings towards his wife; third for your keenness to know what is allowed in Islam and what is not though you are not formally Muslim.
With regard to the issue of polygamy, I would repeat what I give in every answer related to polygamy. Polygamy is there in the Shariah; it is an option. It is not a sixth pillar of Islam that every Muslim has to practice.
Polygamy is not the norm; it is the exception. In no way can it be said that a man with two, three, or four wives is better in the sight of Allah than a man with one wife only.
As for the interpretation of An-Nisaa (The Women) 4:3, the verse reads:
{And if you fear that you will not deal fairly by the orphans, marry of the women, who seem good to you, two or three or four; and if you fear that you cannot do justice (to so many) then one (only) or (the captives) that your right hands possess. Thus it is more likely that ye will not do injustice.}
The interpretation of this verse was given by lady Aishah (may Allah be pleased with her). Urwah ibn Az-Zubair narrated that he asked Aishah, saying to her:
O Mother! (in what connection was this verse revealed): If you fear that you shall not be able to deal justly with orphan girls (to the end of the verse) that your right hands possess? (An-Nisaa 4:3)
Aishah said:
O my nephew! It was about the female orphan under the protection of her guardian who was interested in her beauty and wealth and wanted to marry her with a little or reduced mahr (dowry). So such guardians were forbidden to marry female orphans unless they deal with them justly and give their full mahr; and they were ordered to marry women other than them.
Aishah added:
(Later) the people asked Allah’s Messenger, for instructions, and then Allah revealed: ‘They ask your instruction concerning the women . . . And yet whom you desire to marry.’ (An-Nisaa 4:127) So Allah revealed to them in this verse that-if a female orphan had wealth and beauty, they desired to marry her and were interested in her noble descent and the reduction of her mahr; but if she was not desired by them because of her lack in fortune and beauty they left her and married some other woman.
So, as they used to leave her when they had no interest in her, they had no right to marry her if they had the desire to do so, unless they deal justly with her and gave her a full amount of mahr. (Al-Bukhari)
Therefore, the verse in the first place is talking about taking care of the orphans and dealing with them justly. Fairness and justice have to be the norm in dealing with orphans (and everyone for that matter, but we must be very aware of it when dealing with those who are vulnerable).
In case one marries a female orphan, but he cannot treat her justly, he is allowed to marry other women of his choice up to four with the condition of treating all wives equally with regard to spending, clothing, spending time with them, and other material matters which are within his control.
As for equal treatment in the area of love, he is not held accountable for that because it is not possible to control those feelings.
Coming to your own case, you are highly advised to study the marriage proposal carefully. Think of all its consequences for you and the Egyptian man’s current marriage.
If you think that marrying him would affect his wife badly, you have to reject it. Talk to the man frankly and ask him about his reasons for taking a second wife. If you are convinced of the reasons and you are OK with them, go ahead and marry him after repeatedly making prayer of seeking guidance (Istikhara).
If you decide to marry him, make sure that his first marriage contract does not stipulate that he should not take a second wife. If there is such condition, the husband has to abide by it and he does not have the right to take a second wife with his first wife’s permission.
Do not let him do anything behind his wife’s back. You are a woman and you said it bluntly that you would send him off on the wedding night. Theory is different from practice.
His wife would seem that she accepts her husband’s second marriage, but when it comes to reality the situation will be completely different. A word of advice would be that you think it over and over before you take a decision. Perhaps even talk to her.
I would also recommend that you read more and more about Islam to discover its beauty and its peaceful message. We are always ready to answer your queries. Always remember not to judge Islam by what Muslims do.
I hope this helps answer your question.
Salam and please keep in touch.
Please continue feeding your curiosity, and find more info in the following links:
http://aboutislam.net/counseling/ask-about-islam/polygamy-justified-today/
http://aboutislam.net/counseling/ask-about-islam/is-polygamy-better-than-monogamy/
http://aboutislam.net/counseling/ask-about-islam/misuse-polygamy-main-cause-divorce/