Think about this for a moment. Most of humanity, for most of the world's history, has had limited sleeping space, often a single room for an entire family. With that background, you know that sleeping arrangements are just not that important.
More specifically, we have five daughters and for many years they all slept in the same room, all ages. We had a bassinet (big luxury!) for the last two but it was still pretty close in proximity to their room. Sometimes they wake up, sometimes not. Doesn't matter; they adjust to everything. It's what families do.
And try, please for your own sake just try, not to stress or even care about when the new baby sleeps "through the night," which I put in quotes because you will hear it so much. I myself do not sleep through the night, so why should I care if a baby wants to nurse? I did it for years because none of mine ever slept through the night at a young age. It was no big deal; I'd just nurse and possibly change them, not even putting the lights on. Usually no one woke up but me. Sweatless.