After reading a he-said and she-said article that Brittany and Leo did with Entertainment Weekly (abbreivated EW) I've pieced together what happened in Miami for you all...

Timeline: - After filming, producers put Brittany and Leo in tocuh with each other and they decided to go to LA & Miami together - In LA, they rode scooters and crashed into a cactus and Brittany had to see a chiropractor for this later on - They talked a lot about the appearances of the other women and men in the pods during their time together - First few days went well since they were on a high - Brittany's was feeling really homesick and wanted to go home and see her cats this she said led to some crankiness - One of their disccusions they discussed they're "better off as friends" - Another discussion they talked about their schedules and knew they wouldn't fit into each other's lives - During another discussion, Leo asks Brittany if she sees a marriage at the end of this and both agreed no - Leo was shocked they weren't chosen as one of the couples to go Mexico he thought his love triangle secured him a spot on the vacation - Brittany was not surprised her and Leo were not choosing as they had the weakest link out of all the other couples. She wasn't in love with him

Sources: Link 1, Link 2