I don't really have any advice. IL issues are hard. We had major, major IL issues a decade or so ago with my ILs, and it was extremely stressful. My DH is a caring, considerate, loving spouse, but in his family, no one speaks up or raises concerns or talks about anything uncomfortable ever, and I simply could not continue with things the way they were. Fortunately, DH did get on board with realizing he had to have my back and we had to deal with this together. We ended up having a HUGE blowup with the ILs, which I do not recommend. I can suck up and deal with a lot and then just vent privately later, but over time the IL issues just wore me down to the point that I could not continue. Things were very rough for about a year. The blowup happened just before an out of state move, so there was some distance there both emotionally and physically following that blowup. In the next 2-3 years things improved a lot. We set firm boundaries, saw the ILs just 1-2x a year, talked periodically via phone or skype, and that helped our relationship long term, TBH. So it did get better in time. Once boundaries were in place, and I knew Dh was supportive and realized we had to tackle this together, etc. I was also better able to let things roll of my back. Redirecting conversations, sticking with light topics, giving vague statements in response to things, etc. were all easier basically once I felt I was "safe" in setting boundaries and having DH's support.
I now have a pretty fantastic relationship overall with MIL. We now live an hr away from her (vs. out of state). FIL passed away last year unexpectedly, and I'm very fortunate that we had sort of made amends over the years. I will say that I am glad that FIL did not pass away during a period when our relationship was tempestuous.
If you can go and feel okay about letting it all just roll of your back as much as possible, I'd consider going. But really, it is such a complex dynamic and with your DH not really making you feel supported, it makes it that much more difficult to let things roll off of you
Mama to DS-2004
DD-2006
and a new addition-ds born march 2010