If "Let's be totally open with each other" is the party line of your relationship, be careful what you wish for. More often than not, coming clean creates a terrible mess. To help you handle his next explosive confession, we asked experts for tips on how to put out the flames – none of which include screaming or smashing his iPod. Here's what to do when he tells you he…

…has Herpes

This doesn't necessarily mean what you think it means. "When people hear STD, they think promiscuous," says Carole Marks of the department of family medicine at Long Island College Hospital.

"But just one bad decision can lead to a lifetime of painful breakouts." You may be angry that he's been holding out on you, but remember that he's announcing his STD to try to save you from being exposed.

And there's nothing easy about this confession. "He's probably terrified that you'll reject him," says marriage and family therapist Bethany Marshall, author of Deal Breakers.

"He's feeling vulnerable, embarrassed, and possibly even ashamed." Don't demand that he spill his entire sexual history, but do ask him how and when the diagnosis was made – and whether he's been tested for other STDs.

"Find out if he's on suppression therapy; a daily oral medication, in addition to using condoms, reduces the risk of transmission," Marks says. If he isn't, ask him to look into it for your sake.

Be honest about how willing you are to risk getting the disease. "The fact that he has herpes is not necessarily a deal-breaker," Marshall says. "But you might want to delay having sex until you're sure the relationship is serious."

…wants to quit his job to "find himself"

Where, exactly, is he planning to look? "Ask him how he thinks this transitional phase will affect the relationship and how long he sees the transition lasting," says Nancy O'Reilly, a clinical psychologist.

"If he's vague about what he wants to achieve and how he plans to achieve it, be worried."

Backing his resolve to seek a more fulfilled life doesn't mean giving him license to play with his Xbox 360 all day. Your honey should be able to soul-search and pull his weight at the same time, whether that means doing chores or getting a part-time job.

If your combined income will drop significantly, "work together to create a practical plan for the immediate future that addresses your needs too," says Don Rosenthal, co-author of Learning to Love.

Come up with a budget that shows how your household will operate on less money and avoid sacrifices you'll resent him for later; if you need a monthly massage to stay sane, insist on it.

…secretly withdrew money from your joint savings to buy a new flat-screen TV

Stifle your urge to even the score. The issue here is secrecy, not cash. "Call him on his sneakiness and unilateral decision-making, but don't be hostile," says Daniel Buccino, assistant professor of psychiatry and behavioural sciences at Johns Hopkins School of Medicine.

Instead, express confusion. Open with this line: "Help me understand what you were thinking when you spent our money without checking in with me."

Move into an "I feel" statement, such as "I feel hurt and betrayed when you make big decisions without talking to me first" – and finish with a plan of action, Buccino advises.

To avoid future impasses, Scott Haltzman, co-author of The Secrets of Happily Married Women, suggests allotting half an hour every week to talk about financial goals for your shared accounts and how to use funds.

Another good idea: Set up "yours," "mine," and "ours" bank accounts.

"Adults need 'no-questions-asked' money of their own," says Liz Pulliam Weston, the author of Easy Money: How to Simplify Your Finances and Get What You Want out of Life. For big-ticket items, collaboration is still a must.

…changed his mind and doesn't want kids

"This is an instant deal-breaker," says Leah Klungness, psychologist and co-author of The Complete Single Mother.

"It's a clear message, and it's essential to understand that this likely is not negotiable." Changing his mind about his career, where to live, or where to go on holiday won't have life-altering consequences, Klungness says, but "children are the only 'always and forever' commitment”.

If having kids is a must-have for you, hoping he'll magically come around to your point of view only sets you up for disappointment. Klungness adds that news like this involves an element of duplicity.

"Perhaps what he's truly reconsidering is building a future with you," she says. "You deserve better than parenthood with a man who has been and may continue to be less than truthful."

…slept with his best female friend before he met you

Alrighty, then. But why is he telling you now? "Unless you asked for the declaration, this confession seems potentially cruel and hurtful; it doesn't help deepen or advance the current relationship," Buccino says. Which is exactly what you should explain to him.

If he can't give a logical reason for why he felt compelled to confess, make cutthroat inquiries: How long ago did it happen? Does he ever feel tempted to do it again? Does he have deeper feelings for her – or anyone else? Provided you don't have a history of unfounded jealousy, use your gut to interpret his responses.

Trust your feelings, and accept the truth, even if it's painful. By the end of it all, you'll know where you stand – and whether that will be next to him.