If you want to demonstrate to your partner that you respect and care about them, try substituting "I" messages instead. When you start your statement with "I", you are taking responsibility for the statement. It is less blaming and negative than the "you" message.
Try this formula: Your feelings + Describe the behavior + Effect on You
Here's how it would sound.. "When I heard that you had to work this weekend, I was angry that you hadn't asked me first if I wanted to spend time with you".
It takes some practice at first, but with a little patience and time you will be communicating in a more positive way with your partner!