What is light blue capsule with word mutual imprinted on both side?

That would be Vibramycin. It should say either "Mutual 100" or "Mutual 105". It is the only blue pill Mutual has that's imprinted with their name instead of MP. It is a common antibiotic. It's used for things like Strep and the flu, but is commonly used for STDs (Chlamydia, Gonorrhoea, etc.) If this is your partner's pill, I'd say it's treating something you should know about.