Hiya, wow time has flown by hasnt it, glad things are going well for you-not long now!!
On this subject, I gave ds2 ebm for a week when he was 6 days old as he made my nipples bleed and I knew if i continued to feed him off them, I may give up as it was soooooo bloody painful, I was expressing for EVERY feed that he would otherwise had and he was having ebm out of a syringe. After that week and after my nipples had somewhat healed he went back to the breast and fed normally without any problems.
At about 3 weeks I started giving him 2 or 3ozs of ebm from a dinky feeder, not for any real reason, just so he got used to having the occasional bottle, I would then b/f him afterwards if he was still hungry.
I would say that your dh taking over feeding completely for a few nights a week is probably unrealistic, I think your find that (A) your supply will suffer (B)The baby may get lazy(as its much easier/much less work for a baby to bottlefeed than breastfeed) and then reject breastfeeding.
I would say, yes it can work to do it before 6 weeks, but would say that its a good idea to only give a few onces then feed after if still hungry(or the other way round, whichever you prefer), this way baby is still suckling and still stimulating your supply.
Also be aware that giving the odd bottle can become a habit then if you dont set rules(as a pp said, only 1 a day or something) for instance, i started giving a bit occasionally-2/3 times a week, then i started giving a bottle in the evening, then 2, then my supply started to suffer and I had to work hard to bring it back up to what it was.
At the end of the day, do what works for you
hth somewhat, good luck 