MMC has chronic migraines (?) and a laudanum addiction?

This is driving me nuts. I read a book around 2016 where the MMC (the requisite duke/marquess, etc., with the requisite estate) is a recluse due to crippling migraines, which he treats with laudanum or some such thing. I can't even fathom at this distance of time how a recluse ends up married to the FMC, but she sort of comes in and saves the day by helping him manage the headaches. For some reason I thought it might be {Lord of Scoundrels by Loretta Chase}, but I re-read that and it sure isn't! I depend on the encyclopedic knowledge of this sub...

Thanks in advance!