Sorry, this is long, didn't want to drip-feed.
DSS is 6, DH and I have been together since DSS was approx 18 months old. We have an excellent relationship and I also get on really well with his mum. I know she found it really hard at first and still has moments where she finds it difficult but we've always been open and honest about our feelings and have never had any issues. She's engaged to a lovely man and we often all have meals and spend time together with DSS.
We have DSS every weekend, fri-sun evening and half of each school holiday so probably quite a lot compared to many step-families. I have no children so he is alone when he comes to us and this is my first experience of parenting.
Here's the problem...DSS will often accidentally call me 'mum' and then correct himself. I don't correct him because (a) he ALWAYS corrects himself straightaway and (b) I don't want to seem like I'm criticising/rejecting him by jumping in with 'I'm not your mum!'
Anyway, last week he did this but then said 'actually, can I call you mummy as well?'. I immediately thought of his mum who would be absolutely gutted if she even knew he'd asked and I said that she was his mummy as she'd made him and carried him in her tummy - referring back to an earlier conversation we'd had. I also said that everyone only has one mummy but I really like looking after him and even though I often did the same things as his mummy, it wasn't fair on her as she will always be his one and only mummy.
I found it really hard and was trying to get the message across that I love him so much but his mum would be so hurt if she knew he'd even asked that question. We made a joke saying he could maybe make up his own special name for me as long as it wasn't anything like 'stinky' or something like that!
I really really hope I did the right thing, both for him and his mum. He was really insistent on calling me mum and it was so hard to let him down. I know it was the right thing to do though. But...is there anything more I should do? Or a better way to explain it to him? Or was that ok? Help please!!!!