American psychologist Tara Brach, a prominent exponent of Buddhist meditation and author of Radical Acceptance, proposes mindfulness habits for handling in-laws in the New York Times column Meditation for Real Life column:

• Set the intention to be accepting, patient and appreciative with your in-laws.
• Know that some situations might make you emotionally reactive.
• When these moments arise, breathe mindfully and send a caring reminder to yourself to help regain your balance.
• Whenever you remember, ground yourself in mindful presence by relaxing your body, bringing a slight smile to your mouth, and taking a few full breaths. In these moments, recall your intention.
• Purposefully notice what you appreciate about your in-laws and when appropriate, let them know directly.
• Be mindful of where they might be feeling uncomfortable, vulnerable or anxious, and with care, see how you can be helpful.
• Forgive yourself, and them, for ways your time together may be difficult.
• Pause and fully savor the moments when there’s affection, humor or kindness.