I concur with others that you should see a hematology oncologist. There are lots of types of MM, so comparing treatments to others here can be confusing. He might have "light chain myeloma" as his Kappa light chains are elevated. My husband's were 380 at diagnosis, returned to 1 after induction therapy of Revlimid, Velcade, and Dexamethasone (RVD). They are now up again so he will likely go to yet another regimen, it will be his 4th.
Treatment has its draw backs, for the first few months he felt worse than before. Meds have side effects, cataracts, glaucoma, blood clots, and neuropathy in his case. Sometimes doctors do "watchful waiting." Ask what the pm long term plans are? When would he be treated? Which treatment would be first?
You need to have a Dr you trust and are comfortable with, as you'll be surrendering lots of time with them!
There is currently no cure, but lots of treatment options. I hope you find some answers.

I had MGUS for 6 years and then headaches and facial numbness led to a CT that showed a plasmacytoma in my head the size of a golf ball. Chemo dissolved it in 3 months. Had another tumor in my pelvis 4 years later. It took 6 months to get that one. I’m being maintained on Pomalyst and cytoxin, leading a fairly normal life. I’m 83 years old and feel like I’ll go for many more years. UAMS in Little Rock, AR can’t be thanked enough!

I concur with others that your husband needs to see a myeloma specialist. There are several great doctors that have been doing this for a long time. A general oncologist would not be the best choice. I was exhausted all the time and had back pain. That was my symptom. I was in kidney failure before I got the right diagnosis and treatment. If you aren’t getting the answers you need, find the nearest major medical center that has a myeloma specialist and make the trip!

Consider finding a myeloma specialist as a new doctor or as a second opinion. I have several other doctors that I use as second options. One that I use is a web site all4cure.com they look at your labs and you can ask them questions. They have been very helpful to me. Or using a nonlocal doctor you can use telemedicine.

Thank you so much for the information.