Dreams involving ex-partners and old friends can often reflect unresolved feelings or nostalgia for the past. In your dream, the setting of your ex-boyfriend's house and the intimate moment of changing clothes suggest a sense of familiarity and vulnerability. The fact that your ex expressed being turned on by you could symbolize lingering attraction or unresolved feelings between you two, or a desire for connection that you may be feeling in your waking life.

The presence of his mother, particularly in a vulnerable state, might indicate feelings of judgment or concern about intimacy and relationships. It could also suggest a reminder of boundaries or societal expectations regarding relationships, especially from parental figures.

Overall, this dream might be prompting you to reflect on your past relationships, your feelings towards them, and how they influence your current life. It may also be a good opportunity to consider what you desire in your current relationships and whether you feel free to express yourself without fear of judgment.

If you are feeling nostalgic about the past or if unresolved feelings are influencing your current life, it might be helpful to reflect on those feelings and consider how they impact your present relationships.