Does anyone else feel like their marriage is just... different now?

Not asking for relationship advice necessarily, but like... my wife and I used to be spontaneous. We'd take weekend trips, we'd actually talk about stuff other than feeding schedules and poop colors. Now we're just two exhausted people living parallel lives. We coexist around the baby. Haven't had sex in 3 weeks even though she cleared it 6 weeks post-partum. Is this just the newborn phase or are we broken? Asking for a friend (it's me, I'm the friend)