New material added to this thread uses the phrase being in a relationship rather than being in love. I found the latter phrase problematic because it involves a poorly defined mental state that has changed meaning over time. The former phrase is objectively verifiable by external observers.

I have read a book or two on the Design of Experiments over the years purely for intellectual curiosity; I've never actually defined and run a scientific experiment. So I don't have anything worthwhile to say on the general topic of the relative value of objective vs. subjective measurements in scientific studies.