I've been thinking about this some more and Pearla is absolutely right, OP, breastfeeding or expressing is something you need to make the decision on - it's your body that will be doing the work of making the milk! And you that will be correspondingly much more tired etc.
As a bare minimum I would expect that your DP would need to do the following to support you (based on what my DP did when he was at home, it was much harder when he was away)
All night feeds - he gets up, feeds the baby, winds and changes. You get up and pump. He'll still probably get back to bed first!
As much washing up as possible! E.g. By the time he leaves for work you have all your bottles clean and sterilized. Hopefully you'll then only have to wash up pump bits etc as you go along. By the time he gets home you'll have gone through four or five bottles in the early days so he'll the wash and sterilize those. Similarly he'll do the last wash and sterilize before bed.
It sounds really trivial but honestly my hands were RAW whenever my DP was away, washing up ten or fifteen times a day sucks.
Prep for day - as you will have a big chunk of baby sleep time taken up by pumping, you need other tasks to be as quick as possible, especially if you want to get out of the house! If you're going somewhere all together, you want to time t so you're pumping right up until you leave - that should give you a good three hours before you start leaking! But it means he will have to be in charge of stuff like getting baby fed, changed, into pram, changing bag packed etc.
Time off for you - this is very important. Pumping eats into the time that you would otherwise have to relax / rest so he needs to be prepared to work harder in the evening to make sure you get a bit of time to yourself - a bath, a walk to the shops, a snooze. You need to be as well rested as you can be (difficult at the best of times!) to be relaxed, producing milk etc.
I suppose what I'm saying is that a) it should be your choice and b) if he really wants the baby to get breast milk he needs to be prepared for the fact that exclusively expressing is very much a team effort and the work he will have to do will be a lot more than with formula / breastfeeding directly.
I can't really understand why you wouldn't want to breastfeed directly as that was what I wanted so so much for my DS and me, but that doesn't mean I don't respect your decision about what you want to do with your body - and your DH should do the same!
Agree that maybe talking to a breastfeeding counsellor or going to a breastfeeding cafe before your baby is born might be a good idea.
Good luck whatever you decide.