-*Yeah sis I'm not going to say it but I guess they are right. You are too fast (for us lazies to answer back *smiles*)
Mashaa'Allah! I'll say keep the questions coming. It's better they get answered than confuse you.
About marriage I believe everyone answered you well. Here are my 2 cents:
When a man marries a woman from the people of the book i.e Jews and Christains. She enters a safe place. The man has no problem with her beliefs. One God, he believes in it. Prophet Moses peace be upon him. He believes in Him. Holy Christ Isa ibn Mariam. The muslim man believes in him peace and blessings of Allah be on him. So she has no trouble. Women needing a shelter is given a shelter of a man who doesn't disrespect, belittle OR disbelieve in the facts that she believes in and considers 'HOLy". On the other hand, when a Muslim woman enters a non muslims' house. She's being sheltered by a man who DOESNOT believe in her prophet. Not believeing in his prophethood means he lied about it and the Quraan is not the word of Allah. Astagfirullah! This may create problems for her and her kids. To protect the muslim women Allah has forbidden her to marry non muslim men.
About leaving your husband after reversion to Islam. I suggest your read
surah mumtahina :verse10-12. You see when one says " I bear witness that there is NO GOD BUT ALLAH. that means he is a slave who loves what Allah loves, hates what Allah hates, likes, dislikes, acts, talks, thinks Just as his Lord wants him to do. Or atleast he tries. This is what the shahadah or testification is all about. You testify that you are the slave of the most merciful. You leave some things for his sake, out of his love and as a duty to him. He grants you millionfold reward=)
As per fasting. there are different cases. First fasting is Obligatory on all mature Muslims:
O you who believe! Observing As-Saum (the fasting) is prescribed for you as it was prescribed for those before you, that you may become Al-Muttaqûn (the pious). [Surah baqara:183]
Except those who are ill or old and weak:
(Fasting) for a fixed number of days;
but if any of you is ill, or on a journey, the prescribed number (Should be made up) from days later. For those who can do it (With hardship), is a ransom, the feeding of one that is indigent. But he that will give more, of his own free will,- it is better for him. And it is better for you that ye fast, if ye only knew. [Surah baqara:184]
Which means those who cannot fast due to illness or due to travel should fast later when in good health and at home OR feed the poor for each day (amount is specified). For example my Grandma (85) feeds the poor for each fast she misses.
And for those who became ill and will recover later
The month of Ramadân in which was revealed the Qur'ân, a guidance for mankind and clear proofs for the guidance and the criterion (between right and wrong).
So whoever of you sights (the crescent on the first night of) the month (of Ramadân i.e. is present at his home), he must observe Saum (fasts) that month, and whoever is ill or on a journey, the same number [of days which one did not observe Saum (fasts) must be made up] from other days. Allâh intends for you ease, and He does not want to make things difficult for you. (He wants that you) must complete the same number (of days), and that you must magnify Allâh [i.e. to say Takbîr (Allâhu-Akbar; Allâh is the Most Great) on seeing the crescent of the months of Ramadân and Shawwâl] for having guided you so that you may be grateful to Him. [Surah Baqara-185]
I missed a fast last year because I had mumps. I fasted later. Incase I was to have some permanent problem that kept me from fasting, I was to feed the poor.
Hope this clears things a bit=)