Same sex relationships in prisons and subs aside, I actually think intimate relationships between a confined team that works and lives together is a bad idea. The team needs to depend on each other hugely and having the emotional demands of a intimate relationship could make things pretty difficult for those involved directly or indirectly.

Obviously relationships will develop regardless, you put people together they are going to do stuff. It's just a another challenge, in my mind, rather than an advantage.

No different than sex in the workplace, clearly not a good idea, obviously it's going to happen. You hang out with someone long enough, they start being attractive.

Gimlet Media has a fun podcast following a year-long mock space mission. It explores the topic of relationships in a confined space, too: https://www.gimletmedia.com/the-habitat