How early can you give bottles?

Ftm due in May. I want to breastfeed mostly if it works, I'm not opposed to pumping or formula feeding if necessary. I am also worried about getting sleep as I always have had a hard time to go to sleep so I need a long time each night to actually get some sleep. I had read a recommendation that parents take shifts sleeping while the other takes care of the baby, which means a bottle (or two) for my husband. But in the breastfeeding class provided by the hospital, they say wait until 6 weeks to introduce a bottle to avoid nipple confusion but I see conflicting things on how strong that research is.

So how early do you think you can introduce a bottle and still breastfeed? What is the research supporting either way? Again, I am not locked into exclusively breastfeeding. I want to make sure my baby is fed but also taking care of myself.