Different denominations have different views to this, ranging to
outright condemnation to tactful acceptance.
My own pastor (someone whom I respect greatly) shared this once:
yes, divorce is a sin, so are many other things. These are not
issues that will not rob one of the salvation. Of course the
parties concern need to account to God when they meet up
eventually, but life happens, sometimes inspite of everything that
is being done to salvage the situation. Those who married
non-Christians (deemed unequally yoked) need to bear the
consequences of such actions, again, it has nothing to do with
eternal life.
The picture of being unequally yoked has connotations towards the
farming community where two oxens of different size are yoked (the
wooden thingy that pulls the plough) thereby making the entire
farming/digging process extremely difficult.
My personal view? The Corinthians verse does not refer to marriage
specifically but more towards on the general relationship between
believers and unbelievers. It is a warning to potential conflicts
that will arise eventually. Be it marriage or a business dealing, a
Christian need to know that the conflict of interest will be
present.
Unlike some Christians, I do not turn livid when I hear about
Christians wanting to marry non-Christians. It's their personal
choice and they bear the consequences. I can only wish them all my
best. The argument that the non-Christian will pull the Christian
away from God is at best an assumption. Many God loving folks in my
church eventually brought their spouse to church after a long
time.
My church follows the doctrinal stand of being unequally yoked, but
carries it with a tactful understanding and loving heart that God
works for those who love Him.