Hi Bill,
I'm sure your doctor will tell you that there's nothing to be done but get on
with your life, live as healthy as possible and follow his/her instructions
for monitoring.
Hopefully it's much ado about nothing. In other words, it won't develop into
anything later.

Here's what the myeloma foundation says about it
http://www.multiplemyeloma.org/about_myeloma/2.06.asp
MGUS is a common condition where a monoclonal protein is present.
However, there are no symptoms, other criteria for myeloma diagnosis are
absent, and no cause for the increased protein can be identified.
MGUS occurs in about 1% of the general population and in about 3% of normal
individuals over 70 years of age.
MGUS itself is harmless but over many years approximately 16% of individuals
with MGUS will progress to a malignant plasma cell disorder.
Characteristics:
 Serum M protein <3 g/dL
 Bone marrow plasma cells <10%
 Absence of anemia, renal failure, hypercalcemia, lytic bone lesions
 Disease Management - observation

There's a free phone helpline (UK) here
http://www.cancerbackup.org.uk/Cancertype/Myeloma
if you wish another opinion.
Good luck.
J

Your haematologist is giving you good advice.