Successful threesome couples stay committed to each other by establishing trust and communication right from the start. This means having honest conversations about expectations, boundaries, and needs. Couples should also make sure everyone involved is comfortable with the arrangement before moving forward with it. It's also important for them to establish ground rules and ensure that all parties feel respected throughout the relationship. With open communication and mutual respect, threesomes can be a great way for couples to deepen their connection with each other while exploring something new.