At some point it's not worth continuing to discuss something with someone whose basic starting point is so far from mine. But two points do seem worth making.
True, the liberal view (in the world) is that if you love each other, shacking up and having sex isn't so bad. It's what the media lays on us and our children. But God seems to have a different view of things, if you look at the Bible and the law of God in her heart. You can be liberal and not acknowledge it, but it is there just the same.
That is pretty obviously not the question. This is effectively a personal attack, as you are accusing me of advocating things I have specifically said I am not advocating. At some point I'd be happy to talk about the ethics of sex outside of marriage, but since CF will only permit one side, it wouldn't be a very useful discussion. I will say however that I do not advocate sex outside of a covenanted relationship.
But the question is not whether to engage in free love, but whether enough of a covenant exists in this situation that it should be treated as effectively like a marriage. I'm not sure whether I'm unclear or you aren't listening. From what the OP has said, I believe there is a de facto covenant.
You are asserting that nothing other than an official Christian marriage can be a covenant. I believe you are being overly legalistic, and that the Bible itself (particularly the OT) is a more flexible. That's why many states have the concept of a common law marriage. The issue here is not whether we adopt the media's concept of sex, but whether there are grays between marriage complete with license and official ceremony and not married. Liberals tend to take account of gray in ethical analysis. Conservatives tend not to. To me this is a straightforward question of legalism.
But this is not just an abstract discussion. In this case your analysis will create exactly the damage that Christ's prohibition of divorce was intended to prevent. Particularly for the child.
I believe your advice not to marry is also in violation of 1 Cor 7:12 ff. Not technically, but in intent.
Without this covenant, their is no marriage. You made an inference that maybe the husband was not wrong to want to have sex.
I assume this is a typo. If he is actually a husband, the principle is clear enough in 1 Cor 7.