Help if you can please?

Me and my wife are going through a rough time at the moment,before i met her i already had two kids a girl and a boys aged 7 and 8 living with me and now and she stepped in as the mother figure and i love her,my country is in the depths of recession at the moment ,we married 2 years ago and have twin boys who are one and we have a baby due in november,we didn't plan the kids it just happened,we have bad money problems at the moment and we are finding it hard to get time for ourselves seeming we have 4 kids in the house etc,i want to make our marriage work but we keep fighting 6 years ago i was betrayed in my last marriage but i can't let this marriage fall apart as i love her and i don't want our kids to be torn apart either,she has suggested in us perhaps splitting for a while as in she goes to her mom with two of the kids and i stay here with the other two to try and get some of the stress away and stop the fighting i don't want the family to be divided i think it will make things worse i know i did it before but ive an illness since then .we haven't had sex in almost two months but she is pregnant but i feel we are moving apart .The news of the new baby has shocked us but it don't mean we are not happy we are! How do i get my wife to see there is still a relationship there for us and that we can make it work?