As per Keysoe PR transcript index the FULBEY name is grouped with FALBEY, FOLBEY, FOLBIG/G/E, FOB/BIG/G/E, FOBICK, FOOBIG, FOULBECK/E & others. Similar groupings of that name are found on the nearby Bolnhurst PR. While James & Simon are sons of John & Elizabeth FULBEY, other baptisms at Keysoe around that time are children of John & Elizabeth FOLBIG, FOBICK, FOBIG, FOLBIGG, FOBIGG.
The marriage on 23 Nov 1707 is Thomas MAYS bach to Elizabeth FULBEY spinster, both of Keysoe.
These are not instantly available if you search by one name on FS or FindMyPast, I suggest you get the transcripts from the likes of Beds Family History Society.
Regards
John