I really feel for you pigsmayfly and I do think it is sad that people are just not perhaps quite as kind as we would like them to be, partly I suppose because everyone is so busy, and perhaps because there is more of a culture of 'you should be able to do what you want'.
I have four sons. I am hardly ever alone at Xmas because the youngest, who is 27, is still at home with me, which is no consolation at all because he is autistic and he also feels it if we do not get 'invited'. Mostly I do see the others over Christmas but it is always hit and miss as one of them definitely prefers his mother-in-law, one of them I fell out with a while back (long story) and although we speak things aren't 'right' and the other, who stayed with me for two years when he split up with his wife simply prefers the independence of his own space. The thing is I realise that I am very different from them. They are two separate families in a way, the two elder from my first marriage, the younger two from second marriage, and both marriages ended with me behaving badly towards their fathers (although believe me this was not one-sided!). Also, I am into esoteric things, I'm a counsellor and a healer with what many consider a 'wacky' take on life, whereas they are not on the same page at all. So there is not a feeling of 'tribe'. This is increased by the fact that the wives/girlfriends aren't on the same page as me, either. So despite the considerable financial help I've given the elder two, and the support for the younger (I have not been a bad or unloving mother, I don't think) we just don't quite 'vibe'. I try to accept the fact that I'm never going to be a priority. This year son No 3's mother-in-law was 'doing' Boxing Day, so he invited himself over on Xmas Day,.
Boxing Day Sons 1 & 2 invited me to son No 1's new house and all the grandchildren were there and it was lovely - BUT there have been times when it was not like that, just me and my husband (not the father of any of them!) out for a meal on our own, and I always feel uneasy about it. I know a year will come when I do not see any of them, so I try to brace myself. But it hurts - as mothers that's our lot I'm afraid!
I agree with the people on here. however, who have said try to talk about this. WHY do your sons and their wives never come? WHAT is it that your daughter 'isn't going to do again'. It's always best to talk, and to try to understand.
Good luck and a big hug!