I think it?s very hard when one party wants another baby and the other doesn?t, however, something about your first post caught my attention.
?The one thing that I do well and really enjoy is looking after my kids.
I do everything for them, run after them - they are my life.?.
it sounds very much to me as if you want to have another baby, possibly because you don?t feel you have anything else in your life that you are good at. I?m not saying that?s the only reason why, but that it is a huge factor. I can absolutely empathise with the broodyness you are feeling, but is it possible that this is made worse by the feeling that you won?t know what to do with yourself if you don?t have another baby? Your youngest is 4, so will be starting school this year most likely, are you possibly in a position where you don?t know what you?re going to do with yourself when your youngest starts school and that having another baby will fill that void?
It doesn?t have to be like that. You are important too, and as much as you love your children and have the need to do everything for them, there is going to come a time when they?re not as dependent on you, and you won?t be able to have a baby every time one starts school.
I think your self confidence is very low, and that having children is a boost for your confidence because you know that?s something you do well.
You need to take care of yourself, go out, have a coffee with friends, go to the jim and have a swim/work out/just a coffee/chat, go clothes shopping and think about what it is you want to do with the rest of your life, because you do have the rest of your life ahead of you.
Of course you should also explain to your dh how you feel about having another baby, but you also do need to take his feelings into consideration, the desire to not have any more babies can be almost as strong as the desire to have one, and he has a right to an opinion as well.
With regards to wanting to leave if he won?t compromise, you should think about what you?re threatening to do, you have two children, there are no guarantees that you could walk out of your marriage straight into the arms of someone who could/would want to give you another baby, and even if you did these things take time, and by then you might have changed your mind and your other children would be older thus having a bigger age gap which is something you said you didn?t want.
You need to sit down and talk to your dh, talk, but also listen to what he has to say, and perhaps the two of you could get away and have some time together without the kids and build on your own relationship as well.
Good luck x