I can speculate on some possible reasons based on general situations:
Seeking Closure: Your ex might want closure after the breakup and feels the need to talk to you in person.
Regret or Remorse: They could be feeling regretful about the breakup and want to apologize or try to reconcile.
Nostalgia or Loneliness: Your ex might be feeling lonely or nostalgic about the relationship, prompting them to visit you unexpectedly.
Checking Up on You: They might be genuinely concerned about your well-being and wanted to see how you're doing.
Miscommunication: There could have been a misunderstanding or miscommunication, and they came to your house thinking it was okay.
Possessiveness: In some cases, an ex might be possessive or trying to assert control by showing up unexpectedly.
Returning Belongings: If there are items that still belong to them at your house, they may have come to retrieve them.
Accidental Visit: It's also possible that it was a coincidence or unintentional visit.
Remember, these are just possibilities, and the actual reason could be something entirely different. If you feel uncomfortable with their visit or if they continue to show up unannounced, it's essential to set boundaries and communicate your feelings clearly. If necessary, seek support from friends, family, or a professional counselor to help navigate the situation.