In my personal opinion you should get married first and I base this upon 2 issues:
1. Ephesians 4:27 Neither give place to the devil.
Romans 13:14 But put ye on the Lord Jesus Christ, and make not provision for the flesh, to fulfil the lusts thereof.
To continue to live together in the same house is to add undue temptation to sin. Why set yourself up to fall?
2.
Matthew 5:14 Ye are the light of the world. A city that is set on an hill cannot be hid.
Philippians 2:15 That ye may be blameless and harmless, the sons of God, without rebuke, in the midst of a crooked and perverse nation, among whom ye shine as lights in the world;
As a Christian we are to be a light to the world how will it look to any unsaved person that knows you are not married but are claiming to be saved while living together even if you say you are abstaining this puts a shadow upon your witness.