I have mixed feelings on this one.
I think it is very sweeping to make statements that children are better off living in 2 separate homes than to live with both parents who are not getting on.
My parents stayed together for the kids, until I was 18. I am grateful to them for that. My brother was younger, only 13 and is still raging mad in his mid thirties that he had to go and have contact with my dad and step mother and live in general at home with my mum and step father. He didnt want either of these step-parents, in particular he did not want to live with either of them. You only have to read the step parents board to see how complicated things can become. My brother still hates my step mother as they remained in our family home but completely changed the house itself and also the rules in it. So my brother had to completely modify his behaviour, there was now stuff he was not to touch etc when my stepmother was in charge of it.
So if you want my personal opinion on your particular situation op, I think that in general it is ok. But I do not think the fact that you are in separate rooms is particularly healthy for your dc to see. Is there any possibility that you could sleep in the same room but in different beds?
The other thing people often overlook is that ok, you both feel platonic/business partner/sibling like to eachother and this has come about relatively gradually. Now you are using phrases like stay together for the kids. However - have you both really and truly looked into the abyss of being without the other one? You are taking eachother for granted in a way and it could still be the most monstrous shock if one of you gets with someone else. So therefore, from your own personal perspectives, I would consider whether you and your husband could become a bit closer again. I'm not talking sex at this point, I'm just talking a bit of perhaps sitting closely on the sofa or holding hand when out walking. Just small things. There is nothing "terminally" wrong with your marriage, I would be very careful about writing it off at this stage. I think you are in a big, deep rut. You could if you both really wanted to probably get out of it.
FWIW my parents were married 35 years. They still love eachother in some way. My dad would have my mum back if both their partners died. My mum would consider living with my dad as well. Despite the fact that when we were kids, they were really, really shouting and raging with eachother and living separate lives essentially. Be careful. Raising kids is hard, it takes its toll.