Sex addiction divides expert opinion, but for some people it is a very real condition that can be shameful and even "life-destroying". As relationship charity Relate calls for help to be made available on the NHS, two sufferers speak about the impact it has had on their lives.
"At its worst, even having sex five times a day wasn't enough."
Mother-of-three Rebecca Barker said the compulsion took over her life in 2014 and ruined her relationship.
Her addiction meant she was constantly asking her partner for sex.
"It was literally the first thing I thought about when I woke up, I just couldn't get it off my mind," said the 37-year-old, originally from Tadcaster in North Yorkshire.
"I felt like everything reminded me of it. I think it was linked to my depression and the lack of serotonin. I felt like my whole body was craving it.
"It was giving me the instant hit and five minutes later I wanted it again.
"I became a hermit, I stayed at home because I felt ashamed that it was all I could think about. Even though no-one could read my mind, it still felt very uncomfortable for me to be around other people."
Ms Barker's addiction caused serious problems in her relationship. Though her partner enjoyed the attention at first, it became insurmountable for the couple.
"At first he was fine with it but towards the end he couldn't understand it at all. After a few months he started to raise questions about why and where it was coming from.
"He accused me of having an affair - he thought I must have been feeling guilty about it and that's why I wanted sex with him."
In November 2014, Ms Barker "needed a break" from the relationship and went to stay with her mother.
"When I left, I told my partner I needed to get better. He let me go, then the relationship broke down very quickly after that.
"I was under the care of a psychiatrist at the time - she kept saying she would alter my medication but she never said there were any support groups or anything."
Ms Barker was diagnosed with depression in 2012 after the birth of her third child. She said after it intensified in 2014 she changed jobs, split up with her partner and moved to France.
"I made many lifestyle changes in order to get over the depression and the addiction and for me that has worked," she said.
What is sex addiction?
- Relate defines sexual addiction as any sexual activity that feels "out of control".
- The Association for the Treatment of Sex Addiction and Compulsivity says its number of sex therapists has doubled in the past five years to 170
- A questionnaire completed by 21,058 people since 2013 on the Sex Addiction Help website revealed 91% of those seeking help for sex addiction were male
- The largest age group of 31% was aged 26-35, 1% were under 16 and 8% over 55
- The World Health Organization is expected to approve the inclusion of "compulsive sexual behaviour disorder" in its International Classification of Diseases (ICD) list in May 2019
- The NHS says experts disagree about whether it is possible to become addicted to sex and points to Relate for further help
Graham, whose name has been changed to protect his identity, said his compulsion led him to cheat on his wife with "hundreds" of sex workers, leaving him with "rip-roaring guilt".
"When you are in full-blown addiction you are obsessed with thinking about it - from the moment you wake up to the moment you go to sleep.
"It was a horrible, gross experience - there is nothing sexy about it. When you wake up in the morning with a dose of chlamydia, it is not sexy.
"It is damaging and life-destroying."
Graham, who is in his 60s, estimates he paid hundreds of pounds a month for sex over several years, even building relationships with some of the sex workers he saw.
"What started with one affair at work led to another - but unlike most office affairs which may stem from one partner being unhappily married, mine was an addiction which I had to feed each day.
"You have one affair and then you want another and another one.
"I soon realised that the quickest and most convenient way for me to feed my addiction was to pay for it. I would be seeing escorts, sex workers, three or four times per week.
"It is just like being an alcoholic, it's a cycle that builds up in your mind - you feel a high from thinking about how it might happen and then you act it out in the way you planned.
"Then when it's over you feel remorseful, you say you're never going to do it again."
You might also be interested in:
Graham stopped leading his "horrendous double life" when his wife found an email and confronted him.
He sought help from Sex Addicts Anonymous (SAA), which has 78 self-help groups around the UK, and said he has abstained from extra-marital sex for several years.
"When I was found out, I remember feeling 'thank God - something might change'.
"I went to SAA which is an abstinence-based treatment. I call it going from shame to grace.
"It is such a relief to go to the meetings and find out there are other people who are just as miserable and sordid as you are.
"For people who are in this situation, I just want them to know that there is a way out and you can break the cycle."
Peter Saddington, from Relate, said there is some therapy and group work available for sex addicts, but most of it is private.
"[Addicts] realise it is causing harm, but they can't stop and they recognise they need help in changing it.
"For alcoholics, there is Alcoholics Anonymous, but they can also go to the NHS [which] provides support for people who have alcohol or drug problems.
"It would be appropriate that [sex addicts] can go to their GP and get support because it has a crippling effect both on them, on relationships, on their families, their financial situation and their mental health."
A Department of Health and Social Care spokesperson said: "People who think they may have a sex addiction can seek advice and help via NHS Choices, which includes contacts at Relate, Sexaholics Anonymous, SAA and ATSAC."
For more details on addiction charities, visit BBC Action Line.