Can married couples handle abstinence or safe $ex?

It's called monogamy and trust. Most couples know that safe is not necessary within a marriage because the couple SHOULD only be sleeping with each other. So why on earth would they practice these "safe " methods. If the goal is pregnancy prevention, then birth control pills, patches, shots are available. Also, condoms, tubal ligation, and vasectomies are options as well. They're not 100% effective but nothing ever is 100% effective. And, FYI, "outercourse" is not 100% effective either. Those sperm can easily swim in if some are near the genital area. Why get married if you can't trust your partner to be with you and only you and be monogamous? Why prevent against STDs at that point? That makes no sense...