Under Scots law, Ms Sturgeon can still be called as a witness to the trial regardless of whether or not she is married to Mr Murrell.
While it was previously the case that wives and husbands could refuse to testify against their spouse, the “loophole” was scrapped by the SNP in 2010.

Wait, she’s married? To a MAN?
Can they both be each other’s beards ?
A more cynical chap ( ahem ) might think that this was a separation-of-convenience, like when Tessa Jowell and her hubby “split up” after he had been caught taking bungs off of Berlusconi.
Already shacked up with a woman according to some reports.
Next you’ll be telling me Humza Useless isn’t a true Scotsman
SadButMadLad,
who, Sturgeon or Murrell?
BiP, let’s just postulate hypothetically that the marriage was never consummated, that both parties were happy with that arrangement, and that both enjoy the aroma of lavender?
It’s a sham marriage, but that’s ok because these two homely fraudsters were running a sham political party. Their crimes are real tho. It’s just taking forever to investigate because the Scotch cops don’t want to.
Who gets fake-married in 2010? Weird. But anybody who would con you about their “marriage” would steal your gold fillings. It’s not an innocent lie, it’s a pattern of dishonesty and disrespect.
Indeed. People who make such a virtue of their own LGBTQWERTY+ friendliness, and legislate to that effect, decline to reveal their own orientation and appear to take steps to hide it, going so far, perhaps, as super-injunctions? Just speculating there, natch. Most curious.
She’s turning into a beautiful old bird, isn’t she? Doesn’t look raddled and bitter in the slightest.