No parent is entitled to kid-free weekends, as you seem to think.
And why not? Frankly, if my DD is being well cared for by someone competent, trustworthy, and who has her best interests at heart, why should I not feel okay having an occasional weekend away? Seriously, I am perplexed by this. I know many women where I live who regularly rely on their own mums or sisters to take the kids for weekends - I wouldn't do it often, but I am envious of those who have the ability, and frankly - heartsick that my mum lives too far away to do the same, as I know it would be wonderful for her and for my DD. Anyway, I certainly am not going to stick out the next 16 years without a child-free weekend with my DH. If you want to, I won't judge you openly for that.
Maybe not but my DH never says he has 2 DSs and a DSS - he refers to them all as 'our' DSs and ' our eldest DS'. Whatever he may feel, they are treated exactly the same and he has an equally good relationship with all. All the DSs have 3 lots of grandparents and they treat them the same. We are one family.
My DSCs are my family - we are "one family" and I know they think of me, and my extended family, as "their family". But they would be hurt and aghast to hear me speak of them as "our" kids. They don't want that. They know exactly whose kids they are. They are not mine. We can all accept that and still care for one another. That is what works for them, the kids, so why should any one else think they have a better answer...? Again, stepfamilies come in many varieties; this is not a 'one size fits all' life we are all living...