Some episodes are milder than others and it would be nice to know how much to brace myself for each week. I really like the plot and everything is interesting (ie don't want to stop watching the show), but it's upsetting sometimes how there is a lot of sexual violence in certain episodes and as a survivor of sexual violence I want to prepare myself mentally before watching those.
The IMDb page for Game of Thrones has a Parents Guide, which has sections for “Violence/Gore” and “Frightening/Intense Scenes”.
This guide includes episode references, and fairly specific descriptions of any scenes which include sexual assault or similar. Major spoilers are hidden by default, unless you hover your mouse over them (similar to this site).
This page seems fairly up-to-date: the latest edit was 13 hours ago (as I write my answer), and includes details of an episode aired last Sunday. I looked around for other similar resources, and most of them hadn’t been maintained.
Individual episode pages also have a “content advisory” for Parents, with a link just below the cast listing. However, not every episode has this page.
Disclaimer: I don’t watch GoT, so I can’t testify to its accuracy or completeness.
ETA: I should also point out that the IMDb editors don’t get to see GoT in advance, so this is only of help if you’re willing to wait for this page to be edited before you watch the latest episodes.
The Guardian website is running an episode by episode guide.
Each recap contains a considerable level of detail regarding the violence and sexual content in each episode. Unfortunately it's incredibly spoilerish so I'd suggest you read the books first (where the emotional content will be far easier to cope with) , then use the guide to help you with the TV show.