Only one spouse can split pension income. (You can split the pension of one spouse and then the other to see which scenario is better overall but in the end, only one spouse's eligible pension income can be split with the other spouse.)
If it's your income that you'd like to split, navigate to the Pension Splitting screen and select that it's your pension you want to split.
https://turbotax.community.intuit.ca/replies/2647840
