This whole expectation thing is very interesting. I was reading yesterday about Trust and realized there are trust implications in expectations.
We expect that the bridge we drive over will not collapse. We trust the engineers who built it, even if we've never met them.
In marriages, trust and expectations are closely aligned. I trust STBXH will act responsibly when he has his time with the kids. I can also say that I expect him to act responsibly when he has the kids. I expected him to be responsible with our joint checking account -- I trusted him to be responsible with our joint checking account.
See what I mean?
When trust is broken, when someone violates the couple expectation (I expect you/trust you to remain faithful while married to me), then the balance in the R is forever changed, and can only change back with the full participation of the trust breaker.
I think the most important thing in a R is to trust yourself, and know you can handle whatever comes your way. And, to have expectations of yourself -- that you will be honorable, honest, open and fair. Ultimately, that's all we control, and all we can honor.
See: In Trust We Trust This is a link sent to me by the wonderful Wonder, and I found it very useful.