Tinuva
The Magician
+1000err.. yes - I did - considerably stronger than me, and still thinking the weight should be deadlifted off of him. Just about everyone who asks you for a spot seems to expect that - they get a bit of a surprise when I don't touch the bar until they're turning blue.
With regards to my wife spotting me, she has no problem doing so when I was benching 140kg - you do not need to be strong to spot someone - that defeats the purpose. (and I'm not a "light fit guy" - I'm 6.2", 110kg.
She only ever had a problem with dumbbells, but that solved by passing one at a time.
Each to their own, but as soon as I need a spotter that's required to make what I'm lifting more than maximum of 20kg lighter, I'm going to heavy.
If you are a serious lifter, you will know when you are going to heavy, in which case you are going down a road where you will hurt yourself without a beast partner. When you know what you are doing, and how far you can push yourself safely, your GF can spot you, she only needs to move that small feather weight you just just miss the strength for.