Can I re-marry?

Can you re-marry if your spouse is killed in battle? I tried wearing the Amulet of Mara again while around the house-carl Gregor from Dawnstar. So far it did not work. Any suggestions?

If you're playing on the PC, you should be able to remarry by using the console:

• Make a backup save
• Select your spouse (either by entering prid <spouse's refID> in the console or by clicking on your spouse's corpse with the console opened)
• Enter the following console commands:
• removefac 51596
• player.removefac C6472
• resetquest 74793
• resetquest 21382
• setstage 74793 10
• Wait for 24 hours.
• Proceed to marry as normal.

^{Source: UESP wiki, "Skyrim - Marriage" article}
If the above fails, load the backup save and try other methods of remarrying.