I found it relatively easy for me to leave Mormonism once I found out it's all make-believe.

But have found it much harder to say no to TBM relatives who insist we spend our holiday dinners with them.

I used to try to make excuses but realize that it's not necessary to justify why I am not interested in going.

A simple, No Thanks is all that's neededbut there must be other reasons why I just can't do that.

Most likely, it's that I don't want them to feel they can blame me for having abandoned them. Which is what they tend to do. I don't quite know how to articulate this but I've felt abandoned by them, right after I left the cult. They have shown no genuine interest in me, so I don't like the charade of pretending everything is wonderful at holidays, when it isn't.
I know lots of people try to grin and bear holiday gatherings, but I am running out of time (health wise) to do the things I want with my life, so this year, it will have ot be simply "No Thanks"

I know exactly what you mean. Probably the greatest thing I've learned from my significant other is that life is short and I don't owe anyone an explanation for anything.

I will not be spending the holidays at my uber-tbm grandma's house, as I haven't for the last few years because at the end of the day I just don't want to.

It's not a good atmosphere, not a good vibe, and I'd rather enjoy the holidays to the max because who knows if it will be my last.

"No thanks" is probably one of the most powerful phrases in my language arsenal.

Jesus: What is that?
Kolobian: The 1st token of the Aaronic Priesthood
Jesus: Has it a name?
Kolobian: It has.
Jesus: Will you give it to me?
Kolobian: No thanks.
Jesus: ... please?
Kolobian: What did I just say?
Jesus: Ok, sorry. Have a nice day.
Kolobian: You too...

My mom hosts a family gathering, either the week before or week after Christmas. As long as she asks if it fits my schedule before she plans it, I will attend, but that's it. If you can't make it, sorry! I'll see you around after New Years.