Hey guys
Sorry been a bit since I posted. On the fence a bit with this one and I tried my own mom before posting here and well she just doesn't get it
Backstory: partners mom is a super control freak who loves to inject herself into my partners life when she comes to visit and often steam rolls over plans already in place. He lets her do it and it drives me round the twist. For the first two years we were together I had begged him to step up and just say nicely 'actually we already made X plan for this event and we would like to stick with that - could you help us with this plan? Etc'
They live abroad so they only come twice a year for about 2-3 months at a time. Usually Xmas and summer. This year they are here the months of April and May due to flights and cost etc

So last year there was a big party as ss had his communion during this time. I went to meal and party afterwards. Originally I had planned to come up to his house while they were at the communion mass and make all the food and that for the party. Then nana arrived and days before the party it all changed and she took over
Which was annoying as there had been a whole plan but okay so. At the party his mother was very poorly behaved and his family which is very large did not talk much to me (I find them very overwhelming as well because I am from a tiny family) this happens at most events as we see his family altogether twice a year and they haven't really gotten chance to know me properly over that time. To cut a long story short sd became unwell as the day wore on so when my partner said this to me, I took over and checked her over. Got her sorted but not without nana standing behind me and loading her three pence every time I examined her or you know blinked

The next day we were going to take ss out to spend some of his communion money. At this point last year I was still engaged so we were doing financial targets so they could learn to save. Sd had her money and ss with 20 euro from his communion could hit his goal. Yay! I was majorly proud of both of them and thought we would have a great day.
Phone rings and it is nana. She gets angry at us spending the communion money on toys, starts screaming at my partner down the phone. after an hour of conversation we did go get the toys but sure it was all ruined by her attitude
The fallout from this event pushed me over the edge and in August last year we broke up for a month, tho obv we got back together after

At Xmas we had more of the same where she actually thought she could critique the present I had bought for her grandchildren. I had bought ss a Harry Potter book and she went on and on about how she has other grandchildren in Canada who have these books and ss is not at the level to read it right now and she knows all about them etc etc. She also at Xmas lied about me to my partner. Sd wanted a certain doll and so I texted her the name and shop and shop code of the doll we needed and she got the wrong doll - claimed to partner she had never been told them when I shower partner the text she started saying she couldn't read text messages etc

As a result of these events I made the choice to have nothing to do with her for the rest of Xmas last year, which meant not coming up to dinner and celebrating with them and had told partner that I would not be coming to the communion party this year. I said if he wanted me at the communion meal I would go to that because I know BM will be there with her partner.

This has led him to try to coax me for the last few months into coming to the party. I have stood firm. Now he has gone to his dad to have him speak to his mom about being nicer to me and backing off. She has said she will 'try to be less judgemental and more inclusive'. He now feels the hurdle to the party has been lifted and is again campaigning for me to go. I said I would think about it but make no promises. This was a week ago. I still feel the answer is no

Last night he calls me to let me know about the details for meal and party. Turns out sd communion party will be IN HIS MOTHERS HOUSE this year.

I am really thinking this is a no-go. No way am I going to put myself through this crap on her turf and I don't believe for a second that she will be magically better. This is a high pressure situation and I don't think I can hold my tongue again like I did last year.
Yet all the people in my life, none of which are step moms, keep saying if I 'don't make an effort I will push him away'

I need some help from the best in the bunch, those who actually know what is going on with step life. I am going to say no and deal with the fall out on both sides. I do feel a bit guilty cause he has made some effort to make things easier for me. But I am just passed the once bitten twice shy phase and I don't think I have enough kindness or grace in me for giving this woman another chance.

Any advice ? Any ideas?