Sorry for the gloomy post, but even if you've considered these things, it's important to remember that life is likely far from ideal on the other side...
One of the wise elements of the Church's laws on marriage is that the alternative is often also very unappealing. If you can see no reason to continue on in your marriage, contemplation of your living the rest of your life without marriage might be what is needed for you to take the trouble to seek out the help you need to mend your relationship.
If you're recently married or otherwise have no children, living on your own for the remainder of your life might not be a big problem, but if you've grown accustomed to having your spouse take care of many things or especially if you have children, the prospect of separating would likely be an absolute last resort.
As you've said your spouse is not Catholic, it is likely that they will take separation as a sign that it is time for them to "move on". While you might be more open to mending the relationship after some time has passed, they might have already moved into a new relationship. While separation between two Catholics might simply give them the time they need for emotions to cool, a non-Catholic would probably begin looking for someone new. Perhaps there is already someone new in the picture and your spouse's 2nd marriage begins just as soon as you give up on him/her.
Since there's a good likelihood there are children involved, consider their life in a single-parent home. As your spouse probably hasn't committed any crimes, the children will now have two families, one of which will include any future relationships of your spouse. Having the children reside even part time in a non-Catholic home would be a HUGE obstacle to their keeping the Faith. Even if they're mostly grown (my own parents divorced when we were teenagers), that non-Catholic home becomes a permanent part of the family and will influence not only your children, but your grandchildren as well. YOU are the only thing keeping your non-Catholic spouse living at least a partially Catholic life.
Even from a worldly perspective, separation/divorce/child support are bad news. Google "Romeo Misses a Payment" or "Divorce Corp". Both are hit and miss, but are enough to scare anyone away from that system.
Will your children be able to continue their education as you've planned? Will you be able to afford to continue with homeschool or Catholic school?
Perhaps you won't have primary custody... what will their education look like then? Will you be able to afford to support yourself while sending child support to your spouse?
I could go on, but I'm sure you get the point. Sometimes, reaching a state of liveable peace, even if you have many crosses to bear, is better than separation.