There is a reason why God gave us the teaching magisterium of the Church. You will not find the words "stem cell research" in the Bible, you will not the term "euthansia" in the Bible, you will not even find the term "abortion" in Bible, that does not mean they are morally acceptable. There are plenty morally unacceptable things in our society that you will not find direct reference to in the Bible.
Here is a link that may help you with a better explanation of the teaching on artificial insemination:
http://www.cuf.org/FaithFacts/details_view.asp?ffID=123
As far as the teaching authority of the Church the bible refers to the church as "
the pillar and foundation of truth". 1 Tim 3:15
And in Matt 16:18-19 :18.
And so I say to you, you are Peter, and upon this rock I will build my church, and the gates of the netherworld shall not prevail against it.
19. I will give you the keys to the kingdom of heaven. Whatever you bind on earth shall be bound in heaven; and whatever you loose on earth shall be loosed in heaven."
Also Matt 18:17-18
If he refuses to listen even to the church, then treat him as you would a Gentile or a tax collector.
18. Amen, I say to you, whatever you bind on earth shall be bound in heaven, and whatever you loose on earth shall be loosed in heaven.
As Catholics we submit to the teaching authority of the Church esatblished by Jesus Christ which he promised to protect by the Holy Spirit
16. And I will ask the Father, and he will give you another Advocate to be with you always,
17. the Spirit of truth, which the world cannot accept, because it neither sees nor knows it. But you know it, because it remains with you, and will be in you.
John 14:15-17
12. "I have much more to tell you, but you cannot bear it now.
13. But when he comes, the Spirit of truth,
he will guide you to all truth. He will not speak on his own, but he will speak what he hears, and will declare to you the things that are coming.
John 16:12-13
The Bible is clear that Jesus did give teaching authority to HIs Church. Obviously a to follower in Jesus' time artificial insemination would be completely foreign. To put every possible moral dilema in the Bible it would take more volumes than we could even imagine. Jesus never said the Bible was our only reference.
2 Thess 2:15. Therefore, brothers, stand firm and hold fast to the traditions that you were taught, either by an oral statement or by a letter of ours.
2 Thess 3: 6. We instruct you, brothers, in the name of [our] Lord Jesus Christ, to shun any brother who conducts himself in a disorderly way and not according to the tradition they received from us.
As far as you not being able to have children with your future spouse this is definately a cross that I'm sure is very painful. In my own case I have one child. Due to a severe heart condition a second pregnancy would kill me. While the technology is available for me to have a surrogate mother carry the child of my husband and I (and I no doubt have a couple dear life long friends that would do this for me) I can not because it is not a moral choice.
I am also an adopted child. My (adoptive) father also could not have biological children. The parents that raised me
are my mom and dad. If this is the man that God has placed in your life then I think God has chosen a special vocation for you. And I believe He has a a child(ren) in mind especially for you. Sometimes it is very difficult to accept that our plans are not God's. But you will never be disappointed if follow God's way over your own.
God Bless you for seeking understanding and respecting your fiance's faith.
I hope you will continue to join us on the Forum.