How much time in London and Paris?
 

I traveled to London and Paris years ago. (don't ask!) I loved them both and would like to return with my partner. We both love museums and seeing all the cultural sights, he especially appreciates art. He does not have much interest in London except for the major museums. If we have ten days, does 3 or 4 days leave enough time to see London?

my husband and I just spent 3 and a 1/2 days in London (first time trip) with one day outside london - we thought it was plenty of time and we can't wait to go back!

You can certainly enjoy 3 or 4 days, but of course no amount of time will ever be enough. It is mostly just a matter of whether you want to favor Paris or favor London, or treat them equally, and I don't think you can go wrong either way.

If you know what is there, you could spend many, many days in London and not be bored. Its a big, spread out city, so try for at least four FULL days to even begin to do it justice.

Paris is my favorite but there is so much to do in London. I suggest if your partner has less interest in London to split the cities 4 for London and 6 for Paris. I am sure he will want to return to both!