Congratulations on your new LO-to-be!
Personally, I found that DS1 does need to be held/attention...but wearing DS2 makes it EASIER to give them both the attention they need.
I still don't use a stroller, personally. DS1 likes to walk when we go places, or DH wears him. There are definitely times when it's a little bit of a juggling act (ie wearing DS2, DS1 falls asleep in the car and needs to be carried in...) but you just do what you must. DS1 has learned that there's still room on my lap when DS2 is there, just a little farther out towards my knees. And make sure that you're able to give your older LO more one-on-one time....it won't be near as big an issue as you'd think. I was scared, too! Back carries with a newborn can be done, and I tried it, but it really didn't make that much of a difference for us.
If you get REALLY ambitious, you can try wearing them BOTH! (I've done that a few times, but boy, 33lbs on the back and 15lbs on the front gets HEAVY!)
Babywearing Expert, Cloth Diapering Advocate and Breastfeeding Supporter from Nicki's Diapers