Hey Silex...I wasn't just talking about marriages. Friendships as well. It happens, but God really doesn't want us to.
Yes, He doesn't want us to keep company with the evildoers. However, not all unbelievers are evildoers.
The story of Joseph's wife..history stated she was converted to Judaism before Joseph married her. After Naomi's sons died, one of Naomi',s daughter-in-law, Ruth stayed with her to continue to serve her God. When God allowed Esther to married the king, it was all apart of God's plan--to save his people from annihilation.
I haven't read anything of that sort about Joseph. It could be true, or made up. I don't know. However, Ruth is a perfect example of an unbeliever who wasn't an evildoer. When she married the first time, she was an unbeliever. But we see that she was a good person who continued to serve her old mother-in-law and chose to follow her to a foreign land (foreign for Ruth).
When we are yoked up with nonbelievers, there could be long-term consequences. If you look throughout the Bible, the consequences of God's people for yoking up with nonbelievers.
There is a curse that is birthed in us when we join ourselves with people from other beliefs or people that do not serve Christ as God. You see, when you join yourself with people of different religions, occultic organizations, strange god worshippers, or just plain sinners, you are compromising your relationship with God and bringing a curse upon yourself. That's why you can't move forward in your purpose.
I've spent many years living among people of different religions. And what I've seen is that not every non-christian is a bad person. I've come across several non-Christians who have shown kindness, goodness, faithfulness, compassion, love etc.
Look what happened to Solomon. His heart was turned from God.
That wasn't the fault of his wives and concubines. That was his own fault. Yes, they did influence him, but in the end, he made that call himself.
You asked a question, are all unbelievers living in lawlessness? The Bible says what fellowship does righteousness have with lawlessness? To be declared righteous you have to had accept Christ as your Lord, if you haven't you are a lawless person. So, you practice lawlessness which is without regard for God's commands. Yes, all unbelievers are living in lawlessness.
Read Romans 2. Paul talks about some Gentiles who did not have the law, but by nature lived their lives according to the law.
Not all unbelievers are evildoers and lawless people. We, by nature, have the choice to either live a good life or to live an evil life. And there are many non-Christians who live the good life. They live a good life, not a perfect life. Yes, their good works will not get them to Heaven.
The point is, not every unbeliever is an evil person. There are those who live in absolute disobedience to God and His laws, and these are the people we should not mingle with.