You are on your own in the office
I used to work with a Mr Morris and a Mrs Morris who went on a business trip together. Their host thoughtfully provided them with a double room.
Unfortunately, Mr Morris was gay and Mrs Morris was 15 years older and married to a different Mr Morris. The arrangements had to be changed rapidly.
But the thought was kind. In fact, sharing a double room on a trip is one of the few concessions made to an office couple - apart from anything else, it usually saves money.
Otherwise, you should abide by some pretty restrictive rules:
lno kissing in the office (do not even think about anything more intimate);
ldo not used the loved one's face as your screen saver;
lif you have pet names for each other, never let them slip out;
lnever discuss childcare arrangements in front of a third party;
lnever straighten his tie/ brush dandruff off her collar;
ldo not send big bouquets to the office on birthdays/St Valentine's Day - you both have homes/a home for heaven's sake; and ldo not back each other up overvociferously in meetings.
And even if you do break one of these rules, whatever happens, never argue on the premises. If you do, the people who already resented your relationship and the ones who until now have regarded you both indulgently will huddle in corners to say: 'I told you it would never work.'