Realistic Itinerary for London 3 days

You are touring inside St.Paul’s and Kensington Palace but skipping Westminster Abbey which needs to be seen inside. There is so much history, coronations and funerals of royalty! I lGraves of literary greats and more. I visit it on every trip to London.
Also too bad you won’t get inside the Tower of London.
If Buckingham Palace is open for tours, sign up! It was a very good experience for us. Self guided with audio.

Everyone has their own "must sees". It is a little hard to comment on your choices since they are so different than the ones I might make. I'll try not to be too negative but give a few pieces of constructive advice.

Tuesday looks quite strange to me. Walk past Westminster Abbey and other key buildings in that area.
Go to an 11 am event at Horse Guard Parade. Walk past some other places.
Are you really going to spend the day walking past places?

What if you went in Westminster Abbey when it opened and did a self-tour using an audio guide and then proceeded to the Changing of the Guard at the Parade ground? You would have time.

Wednesday is impossibly full. My day would look something like this.
Tower of London as soon as it opens (go In!!) skip tower bridge. Take cruise to Greenwich and enjoy either the Naval Museum, the observatory, or the Cutty Sark before returning up river.
Go to St Paul's on the way back. Climb the dome here for your aerial view and skip the Sky Garden

Another option for going in the tower, but something new for your partner is to go to the ceremony of the keys in the evening.

Thursday pick two. One for the morning and one for the afternoon.

The British Museum is monstrously large and extremely popular. Don't head over there without a plan of attack. Check out the museum's website to decide what areas you want to focus on. My Walks of London guide said the Egyptian gallery is usually the most crowded. He warned us that the museum is especially mobbed on rainy days.

I'd seriously consider going inside Westminster Abbey. For me, it was outstanding. Same goes for the Tower, you're not going to see much by walking by.

I'm going to London for the second time and considering skipping Westminster Abbey again. Is there much to see inside besides graves and memorials? Unlike Rick, I don't have much interest in where dead people happen to lay. Sorry to hijack, but seems relevant to the OP.

By the way, that itinerary is pretty much what I did in a week in London while visiting a friend (who took me to a fun horse riding lesson, too!) It seems a bit tight for 3 days. The Tower is a must.

I'm going to London for the second time and considering skipping
Westminster Abbey again. Is there much to see inside besides graves
and memorials?

It's one of those places that I would highly recommend a guide so you understand the significance of what you are seeing. Except for Elizabeth I's grave, most didn't mean much to me either. But the history of the place is amazing. Our guide also told us stories of coronations, the coronation chair, the unknown soldier, etc. Like all sightseeing, you need to determine your priorities and the Abbey was a highlight for me.

Thursday looks horrendous to me and much too busy. Have you allowed time to get between the different places, comfort stops and lunch? Kensington Palace could well take a couple of hours too. Household cavalry Museum - recommendation 45 minutes. British Museum is HUGE and could easily eat uop several hours.

Thanks Everyone. Lots to consider now.

I am long time Equestrian so the Change of Guards at Horse Guard Parade was one of my top picks as well as tour of Household Calvery Museum.

And as I mentioned my partner already saw Tower of London so thats why we were skipping inside; Ceremony of keys is all sold out while we are there. But I will mention it to him again - I read you really need a half day or more at the Tower so that was part of why we were skipping too.

British Museum is not real priority.... both it and Harrods were just end of day thursday maybes.

I might try to add Westminster audio tour Tuesday afternoon since everyone recommends it. but opens at 9:30am so not sure enough time to do it before changing of guards which we want to be at Horse Guard Parade by 10:30am to get decent spot.

My time table was roughly as follows, i tried to plan for stuff in similar areas based on maps to avoid back and forth travel:

Tues
10:30am Horse Guard Parade
12/12:30pm lunch
1:30p Big Ben and house of Parliment walk by
2:30p Westminster Abbey (maybe try to add audio tour)
4pm St James Park/ Buckingham Palace/Gardens (no tours here until June)
5:30p walk to Tarfarlgar Square and then Covent Garden area for dinner

Wed
10am Tower Bridge (this bridge just fascinates me and the glass floor crossing)
11:30am Tower of London Walk by
12:15 Sky Garden - plan to grab lunch here at Cafe
1:30/1:45pm St Pauls Cathedral tour
3:30pm London Eye walk by
4pm Thames River Cruise
Then explore for dinner place. I could maybe push end of day river cruise to later as they run until 10pm and due short tour of Tower of London before or after St Pauls Cathedral tour or skip St Paul? not sure

Thurs
10am Kensington Palace Tour
11:30am Kensington Palace Gardens
12p Hyde Park
12:30/1p explore for lunch spot
1;30p/2pm Household Calvry Museum Tour
3p open (maybe british museum or Harrods)

We all have our priorities, but I also find it a bit unusual that you’d rather walk by Westminster Abbey and go into Harrods. It feels like maybe you don’t want to do it unless there’s a set tour? I visited Westminster just armed with RS guidebook, and that was plenty to appreciate the place. Imho Westminster is maybe THE essential London sight. It’s worth scheduling your time around. I mean, just “seeing” Big Ben, Parliment, and the London Eye for that matter, takes a matter of minutes standing on Westminster Bridge. That’s not something you need to schedule, but going into one of these places is, and I’d argue is more important. In that same vein, I would not skip St. Paul’s by any means. Certainly not so you can cross town to get on a boat ride. You can pick up a boat at Blackfriars Pier or by the Tower.

The British Museum is incomparable, but you’re tacking onto the end of a very long day with a lot of walking.

I agree that everyone has priorities - of course - but really think that the Tower of London tour is not to be missed. My grown kids and I did that first thing the morning we were to fly out in the afternoon, and never ever regretted it!

I think you will see a lot, but not be able to experience much.
What type of travel memories do you desire to create?

For end of day Thursday, rather than Harrods, what about Liberty? In my opinion it's a much nicer department store in an incredible building, and closer to the Household Cavalry Museum.