There's a long history with MIL which I've posted about before. To cut the long story short: DH had a shitty, bordering on neglect, childhood where his sisters were very obviously favoured and he very obviously was not. Throughout our relationship/marriage there have been MIL issues. I can't post them all or this will be miles long. A few stand-outs are her going table to table at our wedding telling everyone what a bitch I am (because we put the buffet table in the 'wrong' place and let FIL, her ex, bring his DP to the wedding), making highly inappropriate comments about our fertility issues and miscarriages (making a to do about 'finally' getting a GC when SIL became pregnant, reminding me on Christmas Day "wouldn't you have been due around about now if you'd kept it?", telling everyone at a birthday party about my 15wk miscarriage and asking them all to talk to me about it so I could 'address my feelings', etc), threatening to kick my head in when I was 14wks pregnant because she was jealous of DB taking DS out for an hour, lots more things I can't even list.
When the DCs came along the relationship got even worse. SIL has DCs the exact same age and gender and MIL favours them greatly, that's her decision and we weren't bothered so long as she spent at least some time with our DCs too as they are also her grandchildren. The reality of it is that she rarely sees them, despite living just down the road (15 minute walk away).
We stopped taking them to her house when she and BIL started making snide comments about then-2yo DS along the lines of "quick, here's DS, hide the toys!" - she has lots of toys at her house but they're specifically for her other GC. Then she would fix the other GC snacks and deliberately exclude DS and DD so they'd have to watch the others eat. She still came to our house to see them, though sporadically. While here she would tell DS all about trips she's taken with the other GC, once she went on and on about how she was taking them to the railway museum. DS excitedly told her "I like trains!" She told him "oh ... Well ... We might take you too ... " but never did despite him asking her several more times. Then she started cancelling visits or saying she was going to visit but not turning up, always because her DP was "ill" yet it would then come back to us that they'd been out with her other GC.
She made plans to come see DS the weekend before his birthday and didn't arrive. I tried ringing, texting and nothing. I was worried something had happened then around 5pm she got in touch to say her DP was really ill and they'd been at the walk-in centre all day. Twenty minutes later she had pictures on Facebook of her day out with the other GC and her very healthy looking DP ...
On DS 4th birthday a few months ago she sent her DP to the house ten minutes after bedtime with a card with £5 in it. On DDs 2nd birthday a few weeks later she arrived at the door all smiles with cards, balloons and a vtech tablet. That's when we decided enough was enough. We told her we couldn't accept the tablet when DS got £5 just three weeks before and that while we already know that she plays favourites between her grandchildren, she will not play favourites with our children, she either treats them equally (or as equally as possible) or not at all.
She massively kicked off, we were ungrateful and spiteful and were depriving DD and so on. Her DP made some really nasty remarks about me being a "grabby bitch". We've never heard from her since and she hasn't returned any attempts to contact her. In November FIL (her ex) asked DH if he would "allow" MIL to have contact with the DCs and offered to pick them up from ours, drop them at MiLs and then return them afterwards. DH pointed out that we have never refused contact, she was the one who stopped contact, he also pointed out that they are children not parcels to be shunted from one house to the other and that we are their parents not FIL - if she wants to see them she needs to contact us. He very much left it in her court, she knows where we live, etc.
Since then there have been two family parties where we were all in attendance and she blanked us and the children. She's made no effort to get in touch and for all FIL claims that she is heartbroken and pining for the children, her behaviour would suggest otherwise.
Now FiL wants to see DH tomorrow, specifically without me or the DCs there, to discuss "access arrangements" for MiL 
DH has told me he doesn't want MIL to have any contact with them as its too late, she's had chance after chance and clearly couldn't give two shits about them. FIL thinks its time that we said sorry (!) for cutting her out and that we should let her back in because she's family. He thinks that its me who has decided to cut her out.
AIBU to agree with DH that its too late and we don't want her in our DCs lives?