The bible is very clear about fornication. It is a sin and Christians are to abstain from sin of any form. However, this is one of the sins that many Christians courting find okay because it is the norm. I still think
God's word has not changed over time so must we also not compromise....
To give my contribution to this question, I think, Christians courting much not only be accountable to God and themselves but to a christian married couple (married for more than 10yrs) whom they can go to with any chalenge like this one for counselling and guidance. Some of us are upright and still holding on to the Christian faith because there are some people aside God who are constantly checking up on us to make sure we are on course.
Personal responsibility to do the right thing will also go a long way to help. A friend recently told me that "if you cannot discipline yourself, forget about Heaven". Abstainance is a discipline!