One of the big problems with toeiva, is that you are broadcasting a ‘private’ matter and making it perfectly acceptable to be a ‘public’ matter. If chas v’shalom this type of marriage is acceptable, you will have no recourse – you will have to hire, live next to, rent to, watch signs of the relationship in public etc. etc. of such a couple. Meaning your kids will have to be aware of this, discussions will have to be formulated, and what was once private has become everybody’s conversation. Kedushas Am Yisroel can’t tolerate such a law.
I also agree with a previous commenter that once it is permissible, it will be easier to become a ‘viable’ option. I hate to compare it to ‘divorce’ – but i just mean it as an example, that, when it was so not an option, people stayed together, whereas when it is more rampant it becomes much easier to just say, I’m outta here, instead of working things out.
May Hashem help us, listen to our desperate cries to be redeemed so that we can once more be his ‘am kadosh’ and the Shechina can rest between us.
Have Kavana when you daven – it is the best tool we have.