Usually the doctors will monitor baby's growth a bit more closely with additional scans later in pregnancy.
If the SUA was the only finding and the rest of the anatomy scan looked normal, that's generally more reassuring. It might be worth asking your OB whether they recommend any additional testing or monitoring so you know what to expect.
I can understand why you and your hubby are anxious though. Hopefully some mums who have gone through an SUA pregnancy can share their experiences too. 💕