Liz, when I looked at the copy of the marriage register in the Rolls Office in the 1970s, I noted
“16 June 1835 Robert Gill and Margaret Kermeen both of this parish”.
In those last years before the modern form of marriage register was introduced in 1849, little more information was given, but against some entries from that period I have copied “widower” against the groom’s name. My own feeling, then, is that Robert was a bachelor.

As you may know, there was a long thread in August 2013, mostly under the heading “Elizth Sophia GILL bapt 1827 Braddan” Elizabeth Sophia’s parents were Robert Gill and Margaret Gill, but the conclusion of the thread seems to have been that Elizabeth’s parents were a different Robert and a different Margaret from those married in 1835. That probably has no bearing on your enquiry, but if you read though the thread, some of the messages might point you in potentially useful directions.