As above. I'm kind of an ignoramus when it comes to the lives of soldiers, so it's a curious topic.
Follow up questions, if the above ones are fine: Did any of these rules differ for officers? Region by region differences?
Cheers in advance!
Yes, soldiers were not allowed to get married under the Principate. However this didn't stop them from forming unofficial marriages. Under Septimius Severus the law was amended to permit soldiers to marry.
As for officers, yes they were permitted to marry. Some brought their wives with them to the provinces (we have some letters from the wife of one legionary commander inviting the wife of another officer to a party).