absolutely nothing Clare, it takes practice and being relaxed -one word of caution, don't push it too much before babe has the knack of feeding well, that's why 6 weeks is used as a handy start point.
I know what's been going on with you and DP , but if you wouldn't be expressing anyway, I'd think about it very carefully, you could compromise your chances of BF successfully,and DP might not be ready or willing to 'bond' - He needs time to get his head sorted out, as do you and there's plenty of time for them to bond , but you can't do anything to speed up the process.
If it helps, DH was very detached after DS1 was born, we split up when DS1 was 9 months old after a lot of unhappiness on both sides - We got back together after 6 months , but lived apart until DS2 was nearly a year old so lived apart for nearly 4 years