I think the biggest asset my husband and I have is our difference of history. We grew up in opposite ways and made opposite choices. Each of us has areas of strength and weakness that we are constantly revisiting during financial talks.
He usually says, "do what you think is right, babe" and that ends the discussion because he trusts my financial decisions. There have been a few times where we just do not agree. After several days, and advice from trusted sources, it always has to come down to a compromise.
The thing that has kept our relationship strong is we don't say/or express in any way the famous "I told you so". This helps us tackle the consequences as a team and not as enemies.