We start bedtime from birth so even though they may wake up 30 mins later to eat my newborns get a bedtime routine (bath, snack, book, bed) and then are put to bed in their bassinette in a bedroom and are fed, comforted etc in the bedroom in dim or no lights until morning, this helps establish a bedtime routine and bedtime that mine have never even thought they could fight. Our bedtimes have been early from the get go so no need to adjust when they have to get up early when they start school. Depending on teh childs age they haev ranged from 6:30-8:30pm LIGHTS OUT (meaning done with everything).
For example a 6 yr old with a 7 pm lights out (she needs a lot of sleep) gets a bath at 6 pm, a snack after that and by 6:40 at the latest is in bed and we are reading her books. Books end and lights out are at 7. They go to the bathroom when they brush their teeth after snack and take a sippy cup to bed with them so there is ABSOLUTELY no reason to get out of bed. We on occasion lay with them as a treat (we lay with them though until they fall asleep until the age of 2 or 3 when they are able to put themselves to sleep) to just snuggle as it is harder to have snuggle time when they are older but is a very valued quality time if they have siblings.
Once they are old enough to understand we have the rule no out of bed 3 strikes and you get the door closed and we always send them immediately back to bed though they rarely get up as they havent given us much trouble b/c they are used to this routine and are not afraid of bedtime b/c we have always gently parented them to bed. If they start calling excsessively for requests they get the same ultimatum, 3 chances, you may call for 3 needs, after 3 I will not come and I remind them of this so remind them to save thir 3 in case they really need it and usually they wont call, but once after that afraid to use up all 3. But again they rarely call to use from bed b/c they are used to bedtime.
Even with 3 kids I easily have alone time in the evenings, so much so we rarely go out on dates b/c we can do a snack and movie right at home with kids in bed no big deal. But this is b/c my 6 yr old is in bed at 7 and my 1 and 10 yr old have lights out at 8. This gives me computer, reading, craft time, dh gets study and TV time and we can have together time. But their bedtimes arent so late we cant eat together as a family.
However I see you have a tiny infant. I would establish bedtime now but remember that the baby is tiny and still has a lot of needs and you may have to go to her during your me time, this will NOT last forever, cherish the time with her now and just remember this too shall pass, they grow so fast. We still had time together when my babies were tiny but it may have just been sitting close together and watching a low TV in the dark bedroom while I nursed a baby and then shorter together alone time. But that time quickly passed.