As Little Difference As Possible
While the Dream Eater you describe seems to be harmless, the Dream Eaters know that humans have an alarming habit of making big deals out of trivial differences between themselves and a history of segregating and exploiting any group that they can slap the 'other' label on. That, and the Dream Eaters have read our paranormal genre, so they know if they get exposed they've got a choice of either getting hunted down by a crossbow-wielding maniac or getting stuck in a needlessly angsty love triangle, and neither one of these really appeal to them.
Thus Dream Eater will behave as human as possible. During the day they'll act like normal humans - eat food with their friends, hold a steady job, have some hobby - basically, do not do anything that would draw suspicion to them. Ideally, they'd get married and possibly adopt/have children - a spouse is both fantastic cover and a steady source of sustenance. If they're capable of having non Dream Eater children - excellent! If they give birth to Dream Eater children, than they'd want to adopt children along with the Dream Eater children to provide nourishment to the Dream Eater children.
Obviously, they should also be emotionally engaged in the marriage. Marrying someone for purely selfish reasons and viewing the other party involved as nothing more than a resource is psychopathic and is a steady course towards divorce, which would be disastrous. If the Dream Eater feels their spouse is trustworthy enough (Hint: Hopefully this is the case, trust is one of those things a good marriage is built upon) than the Dream Eater might even tell them their secret, explaining that there's no harm whatsoever, and as a bonus, their spouse will never suffer from nightmares again.