My DH worked away during the week for two years.
It had to be done but put a LOT of strain on our relationship.
Here's a few things we experienced:
When you only see each other at weekends, a whole week's worth of discussion, chat and rows need to be fitted in in just two days which can exacerbate communication problems.
DH gets left out of the minutiae of DC's life (why it matters that Emily isn't talking to her; why it is so important never to miss MI High etc) and can find it hard to get up to speed over the weekend.
You get used to running the house/child/life your way and can resent arrival and upheaval of returning other half (clothes everywhere, hogging the TV, telling DC's off etc)
Chores which need DH have to be put off until the weekend - so precious weekends end up filled with chores; or the chores simply never get done.
Never get to go away at the weekend. It's DH's only time at home - doesn't want to spend it visiting the in-laws, distant friends etc.
It's easy to get v. tired and resentful doing everything on your own during the week.
Having to find a babysitter just so that you can go to evening class/parents' evening/PTA meeting. No-one else there to pick up the slack when you're ill, car breaks down, running late at work etc.
There are loads more downsides. Only upside for us was that at least DH had a job and we didn't go bankrupt.
My advice would be: DON'T DO IT!