All bad behaviour is a call for love, so to help your partner you will need to inspire them with your own love. Here are three steps to achieving this:
1. Put aside your irritation and hurt and think about what your partner must be feeling to act in a moody or grumpy way. Something is missing for them in the relationship - what could this be?
2. What is missing for you in the relationship? - it will almost certainly be the same thing as for your partner. Start fulfilling this need for your partner.
3. Watch how their mood becomes more positive. If you can genuinely give to your partner, despite their negative behaviour, both of your hearts will open and your problems will fall away. This is an act of leadership and love.