The people in the faith community I used to be a part of are scared of anything that could lead them to cheat on their spouses. Since they view any and all sexual or romantic activity which does not involve their spouse, including masturbation or flirting, as cheating, this leaves a lot of them emotionally stunted and sexually repressed.
Measures I've seen them take, and publicly recommend, to avoid "cheating" include:
Shared social media accounts and/or passwords. (Yes, they're among those who have the "couple" Facebook accounts.)
Draconian limits on Internet use.
Avoidance of being alone with -- or even close to -- a person of the opposite gender, to the point of employment discrimination so that they won't have to share an office with someone they find attractive.
( Jewelfox rants about Mormons' unhealthy, untrusting relationships )
I personally feel that anything which can be destroyed by love, friendship, and emotional closeness, probably should be destroyed. Whether it's a bad religion, a patriarchal society, or just an unhealthy relationship.
If you really love someone, you don't stop loving them just because you (or they) have found someone or something new to love. Whether it's a person, profession, or hobby. And I say this as someone with two autistic partners, who both have intense focus on interests which dominate their lives for months or years at a time.
I don't love them despite that, I love them partly because of it. I love seeing them come alive, with the same excitement we had for each other right when we declared our romantic intent. They're more fun to be around, and more fun to snuggle as well.
I'd have to lock them in boxes to keep them from finding new things to excite them. Sort of like what Mormon spouses are taught to do to each other.