Title says it all. Assume this ex-lover was a long term relationship where both at one point believed marriage was in the future. Talking about true love here not some short fling. Seems it's real easy until the other person finds themselves someone new. I'm struggling with this myself. We are, were best friends, mainly due to the amazing connection we built through the relationship. So someone else comes in the picture, what do you do? Lose your best friend or stay together for the kids (you kids of course) and watch her hold another guy how she used to hold you? It would be much easier if she wasn't so beautiful (inside and out). How have you guys handled this in the past and what was the outcome?
I wouldn't say you couldn't stay friends. I'd almost recommend it if you have kids together - if you two can remain on a friendly basis it would help them cope with your separation better. I feel like relationships often change over the years but society makes it harder to change them because we feel like we have to always have a label. People change so much over time. At this point I would not recommend continuing to live with her, and I would most certainly try to get over the more romantic feelings you have, which will take time. Focus on what you still have in common, the intimacy that doesn't involve sex or romance, the kids, etc. Tell her you really want to remain friends because you have a job to do as parents and that it will be easier if you're friends, and be amenable to respecting any boundaries to make that work for your new lives. And remember that people change over time and these things can happen but it doesn't mean love won't happen for you again. Good luck!