I also have a marriage conducted in Jesus College Chapel of two ordinary people from parishes in Cambridge Town. Mine took place in 1750.
I found the marriage in the transcript of Cambridge College Chapel Registers, Marriages and Burials from the 18th and 19th Centuries transcribed by Eve Logarn, a copy of which is in the Cambridgeshire Collection
It was lucky for me as the marriage was by licence and there was no reference to it in either of the parish registers, so worth checking there if anyone has a missing marriage in Cambridge.
Looking at Comberton marriages I see that there was one in Christ's chapel in 1751, two in Jesus in 1753 and one in Jesus in 1754.
I think, but don't know for sure, that sometimes vicars of various parishes served in college chapels, in addition to their own parish, and it is possible that it was more convenient for them to carry out marriage services there on certain dates.
The bride in my case came from St. Clements parish and in that parish register several marriages were conducted in the 1740's in Pembroke chapel so suggests the vicar did 'do' colleges as well!
Selina