A shorter translation of 举案齐眉
举案齐眉 https://baike.baidu.com/item/%E4%B8%BE%E6%A1%88%E9%BD%90%E7%9C%89
是指送饭时把托盘举得跟眉毛一样高。形容夫妻间互相敬重。
Describe the mutual respect between husband and wife

The act of 举案齐眉 indicates the married couple treating each other respectfully and pleasantly as treating a guest,
Another idiom 相敬如宾 (mutually respect each other like a guest) stated it even more clearly.
The literal translation of 举案齐眉 and 相敬如宾 are different, but the metaphorical meanings are the same, therefore, you can translate both idioms as: &quot;mutually respect&quot; (between husband and wife) or more descriptively: &quot;having a harmonious relationship&quot; (in marriage)
Example sentence:
夫妻倆三十年來举案齐眉，相敬如宾 (In the past 30 years, husband and wife show great respect to each other, having a harmonious relationship)
One of the problem in long marriage is losing respect between spouses. Taking the relationship for granted, they forgot their spouse is still an individual being who expectes to be treated politely and respectfully. You still need to say thank you to your wife when she put your dinner in front of you. you still need to respect your husband's opinion even it is an idiotic one and not laugh at him. Just like you wouldn't do that to an important guest (you can still disagree and debate with him politely)