I don't think there's a protocol as to who you have... you can have 2 strangers from the street, the cleaners etc etc
We had my friend (known since I was about 6 and was a MASSIVE help in the run up to the wedding after my ex-mate & ex-bm went a bit loopy) and we had Matt's best friend.
I think that's a lovely idea having a parent each!
H

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The day I married my best friend

September 21st 2002, Brecon

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- March 22nd 2006 Our family is now complete.