MLMM in chat typically means Men Loving Men Loving Men. This acronym refers to a specific dynamic in same-sex relationships involving three men. It's used within the LGBTQ+ community to describe relationships or discussions related to this type of polyamorous connection.
While "MLM" more commonly stands for "Men Loving Men", the "MM" addition specifies a relationship dynamic involving, specifically, three male individuals.
It is important to be mindful of context when encountering this acronym in a conversation, as "MLM" on its own can also refer to Multi-Level Marketing. Therefore, clarity within the conversation or community should always be considered.