"A placebo effect presumes..."
But you must've assumed that wearing a wedding ring would have an effect, either from urban myths and/which made you do this experimentation to begin with. If you did not even think of this having some truth, like Flying Spaghetti Monsters, you wouldn't go out of your way to test it out. I think you knew it'd be so, you just didn't know how effective it would be (at least as you report it) until you saw it first hand.
The problem with the experimentation without control (which would have been easy) is coincidence and lack of recording. Backtracking simply won't do because previous to the experiment you weren't really that apt to record because you weren't paying attention. I bet you ever eye glistening after the experimentation start you attributed it to the ring. How much side glimpses did you attribute to your natural looks previous, probably zero. Experimental bias. Coincidences too cannot be fully ruled out. Three months, what if Seattle had a huge boon of desperate women, what if it was the season of horniness, what if it were three months of good weather and people were just out and about? It's the 90's what if Rachel and Monica (from Friends) made women want to go out and date more?
Like I said, I'm not saying what you're reporting isn't true, that it doesn't work. I'm just talking about the blank open spaces.
PS True very few social experiments are flawless. Scratch that, any experiment. But there are fewer gaps and inconsistencies when proper methods of experimentation are used. You can't eliminate it but there are fewer doubts.