If there were no guns, the jealous husband can more easily get a knife out of his kitchen.
But he'd have to go and get the knife. And win the foot chase. And the fight. And kill one person...maybe. Not drive over to her parents place and slaughter her whole family. Not get into a running battle with the cops catching innocent bystanders in the cross fire.
And if that's all he could do, then your murder rate would drop significantly as it has elsewhere.