关于“在一起一年半”的英语文案，结合权威信息源整理如下：

时间见证爱情

"A year and a half have passed, and our love has only grown stronger. Time may change us, but our bond remains unbreakable."（一年半过去了，我们的爱情愈发坚定。时间或许改变我们，但我们的羁绊永不断裂。）

珍惜相伴时光

"From the first day we met to now, every moment has been a gift. Here's to another year and a half of shared dreams and laughter."（从我们相遇的第一天到现在，每一刻都是礼物。愿未来一年半继续拥有共同梦想与欢笑。）

表达深情承诺

"I promise to be your rock, your confidant, and your source of endless joy. Together, we'll navigate life's journey hand in hand."（我承诺成为你的依靠、知己和无尽欢乐的源泉。手牵手，我们将共同走过人生的旅程。）

强调成长与陪伴

"One and a half years together have taught us the meaning of love. In each other, we've found a home and a reason to keep growing."（一年半的相伴让我们懂得了爱的真谛。在彼此身上，我们找到了归宿和持续成长的动力。）

诗意化表达

"Half a year has woven our story into the fabric of time, creating a tapestry of memories that will last a lifetime. Here's to the journey ahead."（半年将我们的故事编织进时光的锦缎，织就了一生难忘的回忆。愿未来的旅程继续。）

以上文案均围绕“一年半”这一时间节点，结合情感表达与时间见证，适合用于纪念日或日常分享。