1. Their relationship started off a bit rocky, but soon they grew to become life-long friends.2. It became clear that his 10-year marriage to Iris is on the rocks.3. My girlfriend and I are on the rocks.4. Andy and Cindy's relationship is on the rocks.5. A: How is your relationship with your girlfriend? B: I am afraid our relationship is a bit rocky. We have different interests and we always disagree on things. A: I am sorry to hear that. I am lost in my relationship with my girlfriend, too. It seems that we are going nowhere.6. Our relationship is falling apart.
 rocky on the rocks fall apartthe relationship started off a bit rocky = 某個關係一開始有點不好或不穩定，rocky 是最貼切的英文，可用在任何種類的關係我們的感情不穩定 = We are on the rocks. = Our relationship is on the rocks. = Our relationship is (a bit) rocky. = Our relationship is falling apart.on the rocks 很好用，可用在任何人之間的關係，也可用在生意或財務狀況不穩定。以上是最標準的英文。你也可用以下的說法，雖然美國人聽得懂，但並不常用。Our relationship is fragile.Our relationship is not strong.Our relationship is not stable.