As a teenager in the 1960s, I was part of the generation who considered masturbating and pornography a harmless outlet. These days, I see them as anything but.

During my last relationship, I would get up at 5am, head downstairs and masturbate for hours using internet porn. My partner must have figured out what I was doing but didn’t say anything, despite the fact that real sex between us had become an increasingly rare activity. She wanted sex but I couldn’t be aroused by her; I was too preoccupied with the women online. Even as the relationship crumbled, I refused to recognise this as a problem.

Newly single, I was free to masturbate as much as I wanted, and porn started to dominate my free time. I began to notice a decline in my arousal levels, but no drop in my usage. Soon I was spending an increasing number of hours looking for a video that was stimulating enough to achieve orgasm. If addiction is characterised by desensitisation to the subject, I was addicted to internet porn.

Eventually, I realised I had a problem, and discovered a number of websites with resources to help people like me. Now I understand that porn is big business and, as well as exploiting performers in its production, websites giving it away for free are creating a customer base of addicts.

I’ve since quit masturbating, and have a new partner who enjoys being the sole focus of my attention. And I sleep better now. I’m just sorry it took so long to reach this point.

• Each week, a reader tells us about their sex life. Want to share yours? Email sex@guardian.com.

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