I met M at a university party. He was a great guy, but a friend saw him first so I let it go – he was a nice guy to spend time with, and naturally gracious and kind – I respected him. He did seem to attract some unpleasant women. The “friend” ended up being pretty psycho to him and I was glad when they broke up. Saw him on and off over the years until both he and I had settled down with our respective partners. My husband and he were friends and encouraged a friendship between me and M's wife. It started OK, but pretty soon the lies started – I didn't know they were lies then.

Four years of friendship, she'd tell me how terrible M was to her – that he'd strangled her, that he was a terrible father, terrible husband, controlling of money, refused to be supportive, threatened her – everything she said made him out as a monster. It didn't seem like the man I'd met but I hadn't married him so I thought I must be mistaken. The things she said about M's mother were disgusting. When I met his mum, I couldn't believe we were talking about the same person. She is truly kind. Even now, knowing that there were lies about her son committing domestic violence she just says that she hopes M's wife gets some help to get better.

The separation seemed a blessing – what she'd said made it sound like she was a victim of merciless emotional abuse and control, it only took 3 months and all her lies crumbled. She'd been hitting him, emotionally abusing him – telling him he was no good, that she wished she hadn't married him, she'd been controlling the money, reading his emails and checking his phone, isolating him from friends, being hostile to his family, accusing him of cheating all the time when she was the one cheating and I was stupidly the one covering for her. For four years I'd believed her to be unsatisfied because he was a bad person and she was just too scared to leave. For four years I believed her because I couldn't imagine someone telling so many lies just to keep the person they were supposed to love isolated from the world and under their control. I feel like a noob now.

He's out now, free – almost, she still does her Jekyll and Hyde routine on him and keeps that contact because they have a young daughter. Their daughter is stuck in the middle of her abuse, and used against him, M's wife makes suicide threats to the daughter, tells her that the break up is daddy's fault. Tells her own daughter that I'm evil, and that relatives are evil – isolating her own daughter from love and support.

It makes me sick that we normalise degrading behaviour from women to men and get up in arms about it only when the sex is reversed. He's a good man and a kind person. He walked away from the house he bought and paid for so that his daughter could have a stable upbringing, because he still wanted the best for his wife. He doesn't attack his wife's character, he just wants her to get better, he thinks she's ill. I'm afraid for his daughter – that she's learning to hit and hurt like her mother does.

When they split up, he kept his dignity, his kindness and his honesty. He acted with warmth and love and concern. She spat hate, paranoia and vitriol. She had another man in his bed a month after he left. Until now I just hadn't believed that a woman could do this – I believed the victim could only ever be a woman. But we're all just people, and some people are not right in the head. It took me four years to see this. I've never been more ashamed of myself – to have helped that woman hurt such a good man by supporting her lies.