A parallel-parenting situation is better than an attempted co-parenting situation. If/when things improve, co-parenting will evolve from parallel-parenting. Please do not imagine too many future negatives regarding parallel-parenting. One really cannot predict. It is good to be mindful of possible hurt to the children; be equally mindful of the possible good as well. Remember, the grass is greener where you water it.
I will co-sign this. I've been parallel parenting since the start, 18 months ago, and only now is co-parenting starting to look like a distant possibility, and only because I am feeling ready. If it can be done with a baby/toddler, it can be done with older kids. If anything, your older kids are probably noticing more than they need to see during these co-parenting attempts.
Parallel parenting is not unkind, to H or the kids, it's just one of the many ways that divorce can happen. Your kids being older can understand why you've chosen that route. Mum's rules at mum's house, dad's rules at dad's house. You discuss major parenting matters when they arise and live your separate lives with the kids otherwise. What makes you think it would harm their relationship with their dad? That should be his responsibility to sort out.
In my sitch, we use email for formal matters, text for urgent matters, and a notebook that travels between households for day-to-day matters. The only thing we don't do is communicate in person. It's a sanity-saver.
