Dealing with a significant other's living conditions, especially when they are unsanitary and uncomfortable, can be a delicate and challenging issue. It's important to approach the matter with sensitivity and tact, while also being honest about your feelings and boundaries. Here are some steps you can consider:

  1. Open and Honest Communication: It's crucial to have a frank conversation with your boyfriend about your concerns. Emphasize that your discomfort is not about his family, but about the living conditions which are affecting your health and wellbeing.
  2. Express Your Feelings Clearly: Let him know that you value your relationship, but the state of his house is making it difficult for you to visit. Be clear about the specific issues that bother you, such as the lack of cleanliness and the odor.
  3. Focus on Health and Wellbeing: Frame the conversation around health and wellbeing. Explain that the unclean environment could lead to health issues for everyone living there.
  4. Suggest Solutions Together: Rather than just presenting the problem, try to work on solutions together. Maybe you both could clean up a bit when you visit, or find other places to spend time together.
  5. Set Boundaries: It's important to establish your boundaries. If you're not comfortable visiting his house under the current conditions, let him know and suggest alternative arrangements.
  6. Offer Support, Not Criticism: Make sure your approach is supportive, not critical. You don’t want to make him or his family feel attacked, but rather that you are concerned and willing to help find a solution.
  7. Seek Professional Help If Needed: If the situation at his house is extremely bad, it might be a case of hoarding or severe neglect, which could require professional intervention.