I agree with Quad.
I was a single mum for 9 years and would never have dreamt of "telling" my ex when he was to have our son. That would be plain rude and yes, in the real world, how many people can take holiday from work at short notice ? (If I said to my DP I was off for 2 weeks and he'd have to look after our daughter, that would be unrealistic and has nothing to do with how much he loves her etc). My ex was self employed too and as someone already said, this really doesn't make any difference in many roles regarding time off at short notice. Many self employed people have commitments booked in months in advance ..... to suddenly cancel/postpone those could well have a knock-on effect on several customers and not just one. Fair or not, the business could be seen as unreliable ....
.... I always figured that were I to make demands (as opposed to requests) of my ex and time off, his earning capacity might be affected and therefore, also the child maintenance he gave me.
I also felt that a "you're having him, like it or lump it" attitude would do nothing to foster a civilised, polite, business-like relationship between me and him when it came to negotiating all sorts of issues/care regarding our son.
Such a demand would have been equivalent to him saying he couldn't see our son for x number of weeks, regardless of any plans I had made .....
..... and yes, I know there are some men (and absent mothers) who DO behave like that, but the poster here and her partner do NOT sound like that at all. Her DP sounds as if he takes an active and responsible interest in his children so the theory that she told him she was having a holiday because he might not otherwise agree is ridiculous and selfish. DP doesn't sound like he'd say "no" out of spite - but quite reasonably would like to negotiate dates and practical arrangements.
Any normal person wanting to go away without their kids would ask beforehand, and ideally thrash out a plan of how this would work practically, especially given the distances involved. Again, the "they're your kids, deal with it" attitude misses the point. The poster's DP does not have the same network of friends and/or other mums that the children's mother does and presumably cannot easily approach them himself to see if they can help out.
As another poster said, someone who'd prepared to indulge themselves and in the process condemn their children to a shed load of awkward travelling really isn't thinking of them. Had she not been so bloody-minded this might well have been avoided (by going on another date, perhaps during half term, by enlisting the help of other mums etc).
So yes, I completely understand why the poster here is pissed off because the children's mother has behaved appallingly IMO. What sort of example is that to set to them ? .......... that it's ok to do whatever you want, no matter how it impacts on others.
She has emphasised several times that the children will be welcomed and the necessary arrangements to get them to and from school will be made at whatever practical and financial cost. I feel she has been villified by quite a few other posters rather unfairly when all she's doing is sounding off at someone else's rudeness and thoughtlessness ..... which is a constant topic on many areas of these boards.
Oh and BTW, my son is now a stepchild too since his dad has remarried. I couldn't care less if I was referred to as BM in the context of a written forum. I should imagine most people use this abbreviation for convenience sake as it is far quicker than writing "the stepchild's mother" every time.