Talking of weddings.....

Lots of people who marry for the second time have a low-key event.

I honestly wouldn't worry about it.

Thanks for all the positive comments/contributions. I do agree on the whole and feel as Annodomini has said that they will invite close friends who they actually see. I am not trying to lay down the law, rather invite a discussion and I can see that there will be some family niggles over this. Hey ho!

Invitations to second weddings should be a matter for the couple, surely. Presumably each will have a coterie of friends whose attendance will take priority over rarely seen relatives.

You say you are not a close family, and that these relatives had not included your children in their big celebrations. Your children possibly don’t see them as “close relatives” who need to be included in their significant occasions either, in that case.

I am amazed at all this concern with wedding “etiquette” as if there are some rules you are legally obliged to follow!
It’s an event for 1) the couple and 2) their family and friends. (And not necessarily in that order) That is all.
Who gets invited? That is surely up to whoever is planning and hosting the wedding. No way can parents lay down the law, especially to older AC as Telly wants to do. And in this day and age of couples having a home together before their marriage, of second marriages,marriages later in life, even of same sex marriages, details about the order or number of the bridesmaids, number of best men (or women) where to send wedding presents, whether to send presents etc etc etc is just so much frippery.
Sadly the emphasis is too often on the wedding rather than on the * marriage* but that’s another topic.
But I believe that based on statistics, the bigger the wedding, the shorter the marriage.
Food for thought?

Mountain out of a molehill. I don't think people worry about wedding invitations especially second time round.

That's exactly why so many choose to get married abroad and I can't blame them. No one should feel obligated to invite anyone to their wedding not even their nearest and dearest.

Second weddings are often small affairs . Your AC doesn't have to invite anyone they don't want to. And since these relatives didn't invite your AC to their parties, it's really not an issue is it. The idea of mothers "preferring that people get an invite" is the reason why some weddings end up getting out of hand . Just let it go - I doubt that anyone will be half as upset as you imagine they'll be.

I did ask one of my children if they could possibly invite a relative they hadn't thought of, and who, in the past, had been very kind to me. But it was just one couple, and although I wasn't formally paying, I had contributed plenty in the past, so it really wasn't an issue.
I wonder if inviting the relatives you would like would either spoil the balance of the wedding, or with similar relatives from the other side, escalate numbers.
A popular, current choice seems to be a small wedding, and a later, informal party.

It's up to your adult children who they invite. Second time around and as older people they prefer to keep it low key. We did this and didn't invite anyone except two friends as witnesses. I have to say retrospectively I would have invited our children.

I don't think it matters that some family members are not to be invited to the wedding. There have been weddings in our family to which my DH and I were not invited. We didn't feel snubbed at all.