Stress in a partnership can manifest in many ways, and financial stress is a major stressor in long-term committed relationships and marriages. Feeling financial pressure or stress is a very common issue in a partnership, and it can induce tension and other relationship difficulties.
I think it is best to approach financial stress within a partnership as you would any other stressor. Considering these questions may be helpful:
1) What is your locus of control regarding the particular financial situation? What are you able to control and work on, and what is beyond your control?
2) How can you work on compartmentalizing this issue so that you can work on it during some concrete part of the day while allowing yourself to be present within your relationship/family the rest of the day? This will lead to more satisfying dynamics between you and your family members and less overall tension as you can work on maintaining that relational connection even in stressful times.
3) Does your financial plan necessitate the participation of your partner to address and manage the issue? If so, are you able to allocate a specific time frame to discuss the plan with your partner? Making a date to create a financial plan may help you avoid taking out your stress on your partner. Furthermore, engaging your partner may help alleviate your stress because he/she may be more helpful in addressing the particular financial problem than you might expect, i.e. whether practically or emotionally.
It may come as no surprise that if the stress is severe, it may require more formal treatment. Incorporating self-care into your routine, whether an enjoyable hobby, exercise regimen, or even a spiritual practice (I am a big proponent of a personal meditation routine—even as I have my own difficulties maintaining one), will mitigate stress. However, major life stressors may require the help of a mental health professional to really address and equip you with tools and insights.