But trust - too complicated thing. It requires more than just a good attitude to each other two not bad people. It requires understanding, and hence the similarity of values, life strategies, aspirations, outlook, etc, etc. In general, the whole bunch. Without this heap can not do, because if your loved one looks at life differently, it could easily fail. Not with malicious intent, unintentional, but just because some thing terribly meaningful for you, for him (it) is of no value. And he thinks: "Why should she (he) this garbage, and without it you can easily survive, and even much easier and happier? Will cost, interrupt, and everything will be alright."