Many bachelor parties are pretty tame.
Expectations may be high for a wild time, but then reality steps in. Dinner, drinks, possibly a strip club to watch scantily clad women dance on a stage from far away—that pretty much sums up the "debauchery" he'll experience at a stag party. The Hangover frat-boy antics you may be worried about are mostly a Hollywood invention, which makes for a hilarious movie but bears little resemblance to real life. A missing groom? Getting their faces tattooed? 24/7 drunkenness? Not a chance.
He prefers basketball and beer to naked women who aren't you.
Many bachelor parties cater to the groom's interests, so the best man, a.k.a. chief planner, may organize a pickup game followed by a pub crawl, which classifies the party more as a get-together than a drunken sex fest. More and more grooms are also taking a long weekend away with their bros to golf in Cabo San Lucas, Mexico, ski in Aspen or gamble in Vegas.
You trust him.
During your entire relationship, he's never done anything to make you feel less than appreciated and loved. Why would he start now when you're so close to the matrimonial finish line? He may like the idea of having one last chance to go crazy but if given the opportunity to cheat, he would decline, not out of fear but out of faithfulness to you.
You're planning to have fun at your bachelorette party.
Will you be a Girl Scout when your gal pals take you out for a night on the town? Plan on being as respectful of him as you expect him to be of you.