How do I declare my ex husbands pension payments I now receive

If you received payments from your husbands pension, you should have received a 1099-R.  

You'll get a 1099-R if you received $10 or more from a retirement plan. Here's how to enter your 1099-R in TurboTax:

1. Open (continue) return if you don't already have it open.
2. Inside TurboTax, search for 1099-R and select the Jump to link in the search results.
3. Answer Yes on the Your 1099-R screen, then select Continue.
   • If you land on the Your 1099-R Entries screen instead, select Add Another 1099-R.
4. Select how you want to enter your 1099-R (import or type it in yourself) and then follow the instructions. You can add up to 20 1099-Rs.