they are idiots, true friends would never do such thing, sad that you have been friends with them for so long though...

I hope your husband tells them that, he is worried about them and feels he can’t be friends, until they act like adults and talk to you about any worry they have. How childish, I’m quite worried about their real motive.

I bet those friends are women because I can't see any logic.

Well there's some red flags a flying. So it's either they are petty and childishly jealous or they have a ulterior motive(like they're trying to take your husband away from you). it's time for a serious talk with your husband about having a friendship with those women.

They should explain their reasoning. I don't know if your husband has been commenting to them or you have disclosed information that worries them, but I wouldn't assume that they have ungrounded ill intentions. There are a lot of things in a marriage which can be severely toxic that aren't fighting and wouldn't be seen by most people. Most people could easily be "jealous" not knowing what goes on behind closed doors - passive-aggressive emotional abuse, withholding needed intimacy, cheating behavior, toxic mindsets... I'd say talk to them or find out from your husband and reassess yourself. Maybe there's something you can take away to improve your marriage. I think it's more likely they are either right, or they're wrong with good intentions but misconstrued things that have gone on, rather than that your long-term friends are trying to ruin your marriage now maliciously.

They've been waiting for you to share him with them, and you've been greedily hoarding him to yourself. Some friend!

It seems odd they would do this out of the blue. I'm wondering if you're leaving out details.

what concerns did they have?

Unfortunately, there is not enough information to know how to feel regarding this situation. On one hand, you could be a completely sweet person & these jealous people are just unhappy or miserable people who feel threatened around you. In which case, they’re way out of line by trying to “hog” your husband. (I had an incident where my partner stopped seeing his friends because his ex was in that group - and she did not respect boundaries, but I got blamed for “taking him away” - it was a nightmare. Although in my case, it wasn’t jealousy but a misunderstanding + them not believing him/me). On the other hand, maybe you don’t remember or recognize certain patterns as “a problem” that they do not like. (Again, an example is my friend’s boyfriend would make some excuse to get her to come back home within an hour of her being around us - where we would be literally chilling at a McDonalds at times - nothing shady. My friend would happily go home. We thought it has turned her into some puppet. But meh, maybe that’s her choice... but we were just concerned at first). Some people are assuming his friends are bad, while other are assuming you are up to something. I think I stand neutral unless you decide to update details. Good luck!

they want to **** your husband and are jealous of you