reasons to keep them separate include:
-stress. they're not social creatures by nature... one WILL dominate the other. to you, it'll look like cuddling but this is far from the case.
-feeding two snakes together is a horrible idea. i don't think I need to explain that one...
-if one snake gets sick, both will likely get sick. do you want double vet bills?
-if one has an abnormal stool or regurge, how do you know which one it was so you can keep an eye on it?
-cannibalism. nuff said
-accidental mating

i had mine together when I first got them. After I separated them I noticed the difference right away. They both seemed happier and healthier... and grew MUCH faster! hope this helps!