Do my emails look terrible to anyone else?
Yes! They do.
Do anyone know the solution?
My first instinct is "don't use Outlook", but I'm guessing you have some reason you "need" to. In that case, I'm sure there's some manual on Outlook, or some other user group, that has the solution....
Maybe you have HTML emails turned on by default, and mailman is trashing your line breaks because they're HTML <br> tags or something crazy like that. Try turning off HTML composition, and see if that's helpful.
Cheers,