Theirs had been a happy and satisfactory marriage.是什么意思？

Theirs had been a happy and satisfactory marriage.

他们的婚姻曾经一直幸福美满。

theirs

pron. 他们的，他的或她的；

例句
He would leave the trailer unlocked. If there was something inside someone wanted, it would be theirs for the taking...
他不会给那个活动房屋上锁。里面要是有什么别人想要的东西，他们可以尽管拿。

had

v. 有（ have的过去式和过去分词 ），（亲属关系中）接受，拿，买到；

例句
He claimed that his parents had abandoned him...
他声称父母遗弃了他。

been

v. 用来表示某人或某物即主语本身，用来表示某人或某物属于某一群体或有某种性质（ be的过去分词 ），在，存在，不受干扰，去过了，be的过去分词；

例句
Have you been able to have any kind of contact?...
你联系上了吗？

happy

adj. 幸福的，快乐的，巧妙的，〈口〉有点醉意的；

例句
As long as most people are happy to have the monarchy, the abolitionist position is an arrogant fantasy.
只要大多数人还乐意保留君主制，废除它的主张就是痴人说梦。

and

conj. 和，与，而且，于是，然后，因此；

例句
I spend a lot on expensive jewelry and clothing...
我花很多钱购买昂贵的首饰和衣服。

satisfactory

adj. 令人满意的，符合要求的，[神]赎罪的；

例句
Hopefully a satisfactory solution can be reached without much blood letting.
有望在不引起严重内讧的情况下达成一个满意的解决方案。

marriage

n. 结婚，婚姻生活，密切结合，合并；

例句
Rosie's idyllic world came to an abrupt end when her parents' marriage broke up...
父母婚姻的破裂使得罗茜田园诗般美好的世界陡然画上了句号。