Yeah, sorry - have to agree with what's been said. You're going to need to split them up.
You were mis-sold your dragons in the first place - they don't need 'friends', - in the wild they only get together to mate. Reptile behaviour is different to that of mammals - you might be seeing what looks like 'cuddling' - but it's not, it's dominating, and even if he's unhurt by the bigger one, Luke is going to be very unhappy, stressed (which makes him susceptible to illness), suffering from malnutrition and a lack of necessary UV.
I'm afraid it's a choice between the outlay for an extra set-up, or one of them has to be re-homed.