Being a stepmum is wicked

I became a stepmother to two small girls three years ago, having fallen in love with their father, the author Tim Lott. Having chosen him, I guess I was choosing the whole package. But I didn't know what I was letting myself in for. The first weekend the four of us spent together - Tim and I, and Ruby and Cissy, now 9 and 7 - started well.

They seemed surprised and delighted to find their daddy's "friend" had stayed the night, and peeped round the door giggling.

We had a lovely afternoon in the park, and later a crazy bath in which I ended up, fully clothed, in scented bubbles. The next day I planned a roast-chicken lunch.

Ah yes, the lunch. I remember now. The eldest wouldn't eat it because there was gravy on the plate and so began the first of many tantrums - hers and mine.

How was I going to cope? Although one in three marriages end in divorce and step-parents are now a common part of many family units, none of my friends had stepchildren, so I had no template to copy.

I soon worked out that I don't want to be a mum to them; they have their own mum. Instead, I try very hard to be their friend. We play games, make up songs, I'll read them bedtime stories, do their hair in the morning.

This has its rewards, but as I have cast myself as the good guy, it also has its disadvantages, like being expected to play the tickling game in the middle of The Archers. Or not feeling comfortable telling them off.

Like any family, we have fights, but the tension is much worse when they're not your own children. Not only because you don't have the security of unconditional love, but also because when children are with you sporadically (we have the girls 10 days a month), an argument may be left to fester because they left before you could say sorry.

You can't choose your stepchildren. If you ever split up with your partner, it could be that you never see them again. And nor are they your ultimate responsibility. But then neither did they choose you. And, unlike their parents, they didn't choose to be part of a divorced family. They really are the victims.

Thankfully, since having my own daughter - Lydia, who is now 10 months - my relationship with the two older girls has deepened considerably.

Instead of being just daddy's girlfriend, I'm now the mother of their half-sister. Ruby said the other day that she liked me much more since Lydia arrived.

I think they were always scared I would leave, but now they think of me as family.

Of course, there are still problems and I still get confused about my responsibilities towards them. Stepmums are often not thanked or appreciated - there is no stepmother's day, for instance - although Tim recognises the important part I play in their lives.

The wicked fairy-tale connotations don't help either, particularly as stepmothers in stories are cast as the "bad" replacement of "good" dead mothers.

We need to recognise stepmothers not as the wicked witches of fairy tales, but as women who are trying to do right by children.

In fact, a lot of positive things can come from being part of a step-family - not least that you can send them back at the end of a tiring weekend, and in future years I'll have access to two lovely, adoring baby-sitters.