"I think if just one of us had children it would be much easier. " - I can understand why you would think that, but I am in that situation and I think it's just different, not easier. The fact is, for me, I consider myself a childless adult who can do as she wishes, so to be suddenly tied down by another person's kid is a bit of a shock. Those of you who have your own dc are used to being tied down - not able to just buy tickets for something, not able to just go out for a drink, having to check plans before agreeing to a meal with friends etc.
To be fair, dp doesn't expect me to stand in and parent (though it took a LONG time to get him to this point - there were a few times he just expected it without checking with me, but it was the time he did it and I had to be at work that I think he realised it's not so easy) so my checking now is more about just being with another person than specifically him having dss.
But it is also hard because dss isn't always pleasant to be with. Firstly he is a teen. He has a highly developed sarcastic attitude and it's not very nice. Add to the usual teen stuff (what, why should I, it's so unfair, door slamming etc) and it's hard going at times.
We are also in a tricky situation with the ex. dss is with us all the time but dp still pays £500pm child maintenance. She barely sees him. I'd be lying if I said this didn't piss me right off (even though it's not my money!). She is an unpleasant person - very into having everything designer, over made-up, self-centred, overly entitled, victim mentality. Nothing is ever good enough for her and she loves her life to be full of drama. dss has some of these traits and it's not very nice at times. He refuses to wear any clothes that are not designer, for example. We don't buy that sort of stuff, so he moans to her and she buys it for him (from the £500 CM presumably because she's not buying him food with it because he doesn't ever stay with her now).
Her requirements dictate my life.
A week ago we were going away, she decided at the last minute that dss couldn't stay in her house so she asked if she and him could both stay at our house. My answer was pretty much 'over my dead body', but this caused a lot of stress, having to work out where dss could go isntead that w/e. dp said he could stay here on his own but I wasn't happy with that either (he is 15) - see, bloody constant drama!
For example - dp had to rush away to his parents' this weekend as his dad was taken ill, they live 300 miles away. I would have gone with him but I couldn't because of dss. There is zero point asking his mother to have him. It's just lucky I'm not working right now - dp and ex both benefit from that, but I get my time restricted by having to run my life around dss and very little recognition of that.
So - no, I really wouldn't.
Well, maybe if the ex was dead and the step was young enough!