OP, the thing that confuses me is that you say you love him, but are not "in love" with him.
What, in your mind, is the difference?
I think the idea that one has to be "in love" with one's partner all the time is ….a bit girlish, unrealistic even?
Another thing that worries me is the rose tinted view about how your new life will be. The children are young and will want to know why you left H. They will also be unsettled, may fight more, or feel it's their fault. Your friends may side with your H. Your family may too. All this is NOT a reason to stay in an awful marriage, but is it really that awful?
IMO, it is normal for marriages/long relationships to go through a phase where you are not even sure you like your partner, let alone love, let alone be "in love". This then shakes you into action: something in your life needs to change. You then make the change. The love comes back (often).
If you are friends, and you love him….are you really sure you want to do this?
In your shoes, I would not go straight into the "I don't love you and want to leave" conversation.
Instead, i would choose a good time to have a serious chat, saying you are not happy with your life. Be open and honest. I think you can even say you don't even know if you still love him. I have had chats with DH before, we have been through some shit together, and I have thought of leaving but there was always something pulling me back. A big part of that "something" was the fact that we are best friends, and that we had something to fight for (our family and "us" and maybe, deep down, we both believe the only person in the world to really "get" us is hims and me.). We have had to both acknowledge we needed to do something though, your H has to be on board too.
Don't make the mistake of thinking other people's marriages are all plain sailing with non-stop passion and love.
I always think that if you are friends and love eachother, you should be able to make the marriage work again.
maybe not what you want to hear? feel free to ignore just my tuppence worth.