Allow me to share more than just my "feelings" about this topic and then at the end I would like to offer a very nice solution to the whole thing that would make everyone happy, inshallah.

Let me begin with a few very real facts from Islam, in the Quran, then make a few statements based on emotional and logical outcomes based on the available choices.

I do see your point about finding someone you feel comfortable with and want to make a life with. The problem is, it is not acceptable to Allah. He does not consider what you have as a true marriage, due to it not being within what He has prescribed in His Book.

You may see this man as something very good, especially to you. But have you thought about this, the man does not believe in Allah, as One and only One God. The man does not believe in Adam, Ibrahim, Moses, Jesus and Muhammad, peace be on them, as prophets. He does not love Allah. He cannot enter Jennah. You cannot be with him in the Next Life.

Marriage to such a person will only end in a huge problem. The man would eventually challenge something from Allah's religion, and the woman would have to make a decision to leave him or stay without real Islam anymore.

Another problem would be the children. She would be intimidated by the man's family to allow the children to become their religion, or at least to allow these children to "choose for themselves". And that would be rejected by Allah on the part of the parents. The mother and father of a child are responsible for raising their children in the best way, as believers.

So what kind of relationship is this going to be anyway? You say you love him, but then you don't show much interest in what will happen to him after death. Does that make sense?

The fact is, men and women who are believers in Allah, can only marry other believers in Allah. This is according to Allah's Speech (Quran) to all of us.
Take a look for yourself --

Here is the transliteration:

Al-Yawma 'Uĥilla Lakumu Aţ-Ţayyibātu Wa Ţa`āmu Al-Ladhīna 'Ūtū Al-Kitāba Ĥillun Lakum Wa Ţa`āmukum Ĥillun Lahum Wa Al-Muĥşanātu Mina Al-Mu'umināti Wa Al-Muĥşanātu Mina Al-Ladhīna 'Ūtū Al-Kitāba Min Qablikum 'Idhā 'Ātaytumūhunna 'Ujūrahunna Muĥşinīna Ghayra Musāfiĥīna Wa Lā Muttakhidhī 'Akhdānin Wa Man Yakfur Bil-'Īmāni Faqad Ĥabiţa `Amaluhu Wa Huwa Fī Al-'Ākhirati Mina Al-Khāsirīna

Translation to English:

By sister Umm Mohamed in Sahih International: This day all good foods have been made lawful, and the food of those who were given the Scripture is lawful for you and your food is lawful for them. And lawful (for marriage) to Muslim men are the chaste women from among the believers and chaste women from among those who were given the Scripture before you, when you have given them their due compensation, desiring chastity, not unlawful sexual intercourse or taking (secret) lovers.
And whoever denies the faith – their work has become worthless, and they, are in the Hereafter, among the losers.

Surah Baqarah, (the Cow) chapter 2, verse 221

And do not marry polytheistic women until they believe. And a believing slave woman is better than a polytheist, even though she might please you. And do not marry polytheistic men [to your women] until they believe. And a believing slave is better than a polytheist, even though he might please you. Those who invite [you] to the Fire, but Allah invites to Paradise and to forgiveness, by His permission. And He makes clear His verses to the people that perhaps they may remember.

Surah Al Mumtahinah (the Woman Examined), chapter 60, verse 10

Transliteration: Yā 'Ayyuhā Al-Ladhīna 'Āmanū 'Idhā Jā'akum Al-Mu'uminātu Muhājirātin Fāmtaĥinūhunna Allāhu 'A`lamu Bi'īmānihinna Fa'in `Alimtumūhunna Mu'uminātin Falā Tarji`ūhunna 'Ilaá Al-Kuffāri Lā Hunna Ĥillun Lahum Wa Lā Hum Yaĥillūna Lahunna Wa 'Ātūhum Mā 'Anfaqū Wa Lā Junāĥa `Alaykum 'An Tankiĥūhunna 'Idhā 'Ātaytumūhunna 'Ujūrahunna Wa Lā Tumsikū Bi`işami Al-Kawāfiri Wa As'alū Mā 'Anfaqtum Wa Līas'alū Mā 'Anfaqū Dhālikum Ĥukmu Allāhi Yaĥkumu Baynakum Wa Allāhu `Alīmun Ĥakīmun

O you who believe, when the believing women come to you as emigrants, examine them. Allah is most knowing as to their faith. And if you know them to be believers, then do not return them to the disbelievers; they are not lawful wives for them, nor are they lawful husbands for them. But give the disbelievers what they have spent. And there is no blame upon you if you marry them when you have given them their due compensation. And hold not to marriage bonds with disbelieving women, but ask for what you have spent and let them ask for what they have spent. That is the judgement of Allah; He judges between you. And Allah is Knowing and Wise.

The word in Arabic translated here as 'polytheist' is 'al mushrikaati' and this is the female form of the word. That is because it is not permissible for Muslim women to even consider marriage to a non-Muslim man. The word translated in surah al Mumtahinah as 'disbelievers' is 'al kuffari' in Arabic and this is the male.

Let us consider some of the reasons for this, inshallah.
Number one, and absolutely the most important, is because Allah Subhannah wa Ta'ala has said so. And it is not up to us to even worry about the "WHY" when we have a very clear commandment from Allah telling us to do something or not to do something. The best reference from the Quran is in chapter 4, surah An-Nisaa', verse 65.

Surah An Nisaa', chapter 4, verse 65

But no, by your Lord, they will not [truly] believe until they make you, [O Muhammad], judge concerning that over which they dispute among themselves and then find within themselves no discomfort from what you have judged and submit in [full, willing] submission.

There can be no doubt after this verse, everything is hinged off of our belief and our actions together - not separate. Allah is swearing on Himself in this verse! How strong is that? He is saying we are NOT believers, if we see in Quran or hadeeth a Commandment from Allah and then we don't accept it whole heartily, with no discomfort or reservation in our hearts or minds.

Recall, if you will, the story of Adam in the Paradise and what it was that Allah said to Adam, telling him not to even approach or come near to the forbidden tree. He was not just ordered to avoid eating the fruit from it. He was ordered "STAY AWAY".
OK, now consider this, what was wrong with the tree? What was wrong with the fruit from the tree? Was it poison? Was it spoiled? Did Allah want it for some other purpose?
The answer is, "Who cares?" Allah gave an order, what are you doing, thinking and contemplating the reasons for the order, while you are sitting there eating the fruit?