Sensoji + lunch at Sansada (the literal original tempura shop…prepare for a line) + SkyTree
Meiji Jingu + Takeshita-dori Harajuku and street food
Sure, grab the weirdest Japan-only drink you can find at Starbucks in Shibuya if you want and squeeze in at the espresso bar so you can people-watch the world’s busiest intersection. Then go to Uo-bei for lunch. Great shopping in that area
Not itineraries, but one-off ideas:
See if a Water Bus on Tokyo Bay will fit into your plans so you can experience the city via water, see Rainbow Bridge etc
Ginza for shopping and an elegant snack or meal
https://www.jrpass.com/blog/top-3-torii-gate-tunnel-photo-spots-in-tokyo
Have your husband meet you for after-work drinks at Andaz rooftop or Park Hyatt Shinjuku’s 212 bar
Make sure you’re staying on the JR circle line, and carry about 2-3x more cash than you think you need. Have the most excellent time!