I was thinking about this as I saw my ex at the weekend (accidentally that is). When I first knew him I was in a different relationship and so was he and he was friends with my then partner. We got together about 3 years after both relationships ended.
In the relationship I was in at the time I was unhappy, and eventually I ended it, but not before I had done a stupid thing to try and take the edge off it. My partner called me hamster chops and asked me to call him a silly nickname, which I did because it made things bearable! (Looking at that written down I see how mad it looks). He called me Hammy in public and I started answering to it and things like that.
When I knew my most recent ex through my then partner I was working in banking. Not the hedge fund or megabucks kind just a city branch. He wanted to buy a rather expensive car and came to see me for a loan and I organised it for him.
When we got together he said "Lucy [his ex] and I always thought you were a stupid airhead because of the hamster stuff but when you organised the bank loan for me I realised you were ok and quite intelligent." (note the quite!)
I have a 2:1 degree, a PGCE, an MSc, a senior fellowship and a PhD. They have a collection of 2:2s, 3rd and unclassified degrees, PGCEs and the ex has a CertEd. When I completed my PGCE my first ex said "You will soon be as intelligent as me." (He was the one with the CertEd and an unclassified degree).
I know there is nothing wrong with a 2:2 really.
I laughed my knickers off when I was reminded of it when I saw him in the supermarket. Misogynistic twonks.
Any more examples?