So I will give you a bit of backstory, apologies that it's a bit lengthy.
While myself and my OH were at University, he was living with his parents during non-term time and we were away up north while we studied.
My MIL and FIL were married for nearly 30 years.
2 years ago, it came out the MIL was having an affair with another man and had been for sometime. My OH was told by his mother that she was leaving his dad, had someone else and was leaving the home city. BY TEXT. Out of the blue.
The family home was to be sold once my OH had finished his studies and had found somewhere new to stay- effectively forcing his hand to move out and cut short his studies (he was planning on doing a PHD).
My FIL had to move out to live with his aging mother and to become her fulltime carer.
MIL fast tracked the divorce stating unreasonable behaviour on FIL's behalf- Untrue and contested.
Now, this is where my main problem lies. My MIL, was forcing OH to meet her new partner. It turns out that her new partner was terminally ill and would not see the year out. Everytime the conversation ensued, she would cry and guilt my partner into meeting him- something which he was not comfortable with at first as the whole situation was still too raw for him.
She would not meet us or my OH unless her new partner was with her and we literally went for months without seeing her.
We were emotionally blackmailed into attending their wedding, as she rang us up in tears saying that they were getting married that day in London as his health had deteriorated. We immediately left work and got a train to London to support her.
Please bear in mind that in the two years they were together, we saw her less than once every other month. However, when she needed help we gave it to her without question and I personally believe we have gone above and beyond.
For example, we had her cat for 3 months while she was caring for her partner- never to be offered any money towards supplies/food etc.- to be told that it's okay the cat was clawing up our carpet as that's just what it does. To be told that she wouldn't take back her cat until we'd got a Vet certificate to prove it didn't have fleas!!!!!!
I helped her with the wedding, shopping for her wedding dress last minute (literally an hour before the planned ceremony) only to be told it didn't suit her and she would never wear such a thing, she didn't want to look like a slut on her wedding day.... It was a white scooped neck midi dress from John Lewis....
We helped clean his flat and sort through his belongings once her partner died. Not once did we receive a thank you for any of this.
On the day of his funeral, she offered to come round and iron my OH a shirt as my ironing skills were not up to scratch and she didn't want her son "looking like a tramp infront of her new family". I declined, as it was rather insulting and she'd have enough on her plate during the day without worrying about that!
As soon as she saw us, she greeted every member of the family apart from me and said "I shouldn't have trusted you to iron, look at the state of that!!!" and proceeded to mock me along with her new in-laws. Now, I don't mean to be insensitive here, but we didn't particularly go to the funeral for her partner but to support her. Finding faults with me should have been the least of her worries, yet she still thought it was worth while being rude to me.
Now that he has died, understandably, she is lonely. Both my OH and I work 60 hour weeks and on weekends we just want to slob in our PJ's. If we do not make plans to see her every weekend, she just turns up at the house with a lame excuse like she has bought the OH crisps he likes or that she has half a loaf of bread spare and she thought we would like it.
Everytime she comes in she makes a point of wiping down the kitchen surfaces or wiping her finger along the tables looking for dust.
She also LITERALLY WIPES HER FEET ON THE WAY OUT. 
As i've said, we each work 60 hour weeks so I cannot spend an hour a day cleaning the house but it is in no way dirty.
I have had enough of her incessant need to criticise me when she has been no where near perfect for the past 2 years. She criticises me for the "way i look after her boy" even though I was the one to pick up the pieces when she swanned off for 2 years, rarely seeing her son.
I have about had it with her and I feel like I've given her enough time to stop taking the death of her husband out on us.
How do I talk to my OH about this? AIBU?!?!?!