The most sturdy bed frame for sex must have reliable bed siding and inserts. For that reason, look for a brand that blends metal siding and wood slats.  It should though feature sturdy metal such as steel on the sides. But, as for the inserts, look for hardwood such as birch and oak.  Softwoods aren’t durable and so can’t bear much weight. Moreover, the softwoods squeak a lot.