Sex File: Will our sex lives become boring when we leave our marriages and get together? 

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I have been having an affair with a man for the past two years, meeting up once a week. We have now decided to leave our respective marriages and get together full-time. However, I am worried that without the excitement of the affair, the sex will become mundane. How can we stop that from happening?

Swapping your marriage for a relationship that has, so far, involved nothing more stressful than steamy sex once a week is not going to be smooth sailing. Within those parameters, I'm sure this relationship is perfect, but take it into the real world and it won't be just your sex life that feels the strain. Affairs can seem to pour champagne sparkle on the domestic drudgery that defines family life, and the magic can sustain you for days. The minute you say goodbye, you start looking forward to your next hello. That sense of anticipation alone ensures you are brimming with lust and overflowing with excitement the next time you meet.

I realise that you probably wouldn't have had an affair if everything in your marriage had been hunky-dory, so it is possible that you have simply pre-empted something that was on the cards. Research by the family psychologist Paul Amato, who is one of the world's leading experts on divorce, has consistently found that infidelity is more likely to happen in troubled marriages - which perhaps isn't a surprise. But his research also finds that infidelity increases the level of distress within the marriage. It is not uncommon for the guilty party to try ramping up issues to force their unsuspecting partner to demand change, or even an end to the relationship.

You already know what happens to sex when you sleep with the same person every night, but you have no idea how hard it will be to keep this relationship fresh and fun when you are both battling solicitors and ex-spouses on the side.

Because you have sacrificed so much to be together, you will both be determined to make the relationship work, but be aware that leaving the past behind is no guarantee of a happy-ever-after. In 2017 the psychologist Kayla Knopp and a team at the University of Denver conducted a study of 484 couples through two sets of relationships and found that prior infidelity emerged as an important risk factor for infidelity in the next relationship.

You are also right to be concerned about the impact that getting together on a more formal basis will have on your sex life. You could try to hang on to the routines that made your affair so exhilarating. If you used to meet in hotels, for example, make a point of booking a night somewhere nice once a month; if you snogged in the cinema, make sure you have regular movie nights. Secret sexting? No need to stop now that you share a remote control.

Once you are officially a couple you won't experience the adrenaline rush that the secrecy of your affair generated. You can, however, achieve the same effect by doing activities that raise your heart rate and make you feel excited. People who have affairs are often risk-takers - whatever you do, do your best to avoid boredom.

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