C.W.
I too have twins, boy/girl, now 11yrs. old. You have to do what works for you and them. If they sleep better separated then go with it because that means better sleep for mom and dad and you two need it.
Mine never slept together as they were in born at 27 weeks and were never able to sleep together then the boy was in hospital 2 mths and the girl was in there for 3 months and by then we weren't going to interrupt what was already working. We just kept their cribs close together so they could see each other and when they started standing in them, they could touch each other. Thank goodness we never had any trouble with them trying to crawl out.