Hi, how's it going?? Hope you're all ok.
I was 7(I think) when my parents split up, and they didn't really tell me anything, my mum just started packing and said we where leaving (not the best tac in the world).
To be honest your children probably know alot more than you think, and reasurance is needed. Saying 'it's not your fault' straight away can actually set doubt in thier mind, so try and avoid that! Just let them know that mummy & daddy are still friends and you love them etc, try to explain it as simply as possible and decide before you talk to them how you're going to ask any questions.
My parents used to send me upstairs while they argued, when, of course, I refused to go... they said they had "things to say to each other".
I don't actually speak to my dad now, because of the way he treated me and my mum for years after this, please don't let it come to that with your children!
Of course, you should think carefully about your options now... would it be better for the children if you two just stayed together? Would they know that something was wrong. Even if it makes you uncomfortable to stay with this man, it's worth it for them.
I know its hard not to use the children to get at your partner, but this is SO not the best way to go about things! Try to look at it from a 7-year-old's point of view at least.
Look, your his mum, you should do whatever you think is best for him, not for you. Trust your judgement, as long as it's not a decision made in anger...
Good luck, keep us posted
x