What it is saying is that if you are already married to an unbeliever when you come to the faith, then don't leave them. But, if you are saved and looking for a spouse, then don't become unequally yoked. The two verses are speaking to two different groups. The first verse is speaking to those already married. The second is speaking to single people. That is how I see it.
Katydid is correct on 1Cor.7:10-16. However, the word 'yoked' in 2Cor.6:14 is in reference to our close friends and who we associate with. The word 'yoked' is #2086 in Strongs Exhaustive Concordance of the Bible which is keyed to Thayer's Greek-English Lexicon of the New Testament.