Spock remained unmarried for TOS.
From "Amok Time", Bridge scene when the Enterprise approaches Vulcan:
UHURA: Captain. We're standing by on Vulcan hailing frequencies, sir.
KIRK: Open the channel, Lieutenant. Vulcan Space Central, this is the USS Enterprise requesting permission to assume standard orbit.
VULCAN [OC]: USS Enterprise from Vulcan Space Central. Permission granted. And from all of Vulcan, welcome. Is Commander Spock with you?
SPOCK: This is Spock.
VULCAN [OC]: Standby to activate your central viewer, please.
(Nurse Chapel enters.)
CHAPEL: Doctor, what's going on?
(The viewscreen lights up with the image of a very beautiful woman.)
T'PRING [on viewscreen]: Spock, it is I.
SPOCK: T'Pring, parted from me and never parted, never and always touching and touched. We meet at the appointed place.
T'PRING [on viewscreen]: Spock, parted from me and never parted, never and always touching and touched. I await you.
UHURA: She's lovely, Mister Spock. Who is she?
SPOCK: She is T'Pring, my wife.
That's pretty conclusive.
Fast forward to just after, in the next act:
"Less than a marriage." And since T'Pring chose the challenge instead of the marriage, and then after winning Spock gave T'Pring to Stonn, there was no marriage of T'Pring to Spock. Spock was never married.SPOCK: This is the land of my family. It has been held by us for more than two thousand Earth years. This is our place of Koon-ut-kal-if-fee,
MCCOY: He called it Koon-ut what?
KIRK: He described it to me as meaning marriage or challenge. In the distant past, Vulcans killed to win their mates.
[...]
SPOCK: The marriage party approaches. I hear them.
KIRK: Marriage party? You said T'Pring was your wife.
SPOCK: By our parents' arrangement. A ceremony while we were but seven years of age. Less than a marriage but more than a betrothal. One touches the other in order to feel each other's thoughts. In this way our minds were locked together, so that at the proper time, we would both be drawn to Koon-ut-kal-if-fee.