In-law question for those in long term partnerships or marriages: what is your involvement with your in-laws? Are you expected to manage the relationship or does your partner? Do they attend your family events and vice versa?

I absolutely do not kin keep for my husband and his family. I am happy to attend events and participate but I am managing the relationship. That is on him to schedule and do. That being said my husband keeps his family at a distance for good reason so we don’t see them much anyway.

My husband and I have children. For the kids parties both sets of families attend just because it’s exhausting to have multiple parties. For holidays we don’t host, so it’s all separate. Which I like. I’m not crazy about his family. So the least I can be around them, the better.

That being said, I know people who have great relationships with their in laws and I wish I had that. Unfortunately my in laws suck. Haha

My in-laws have both passed away as has my dad so I honestly regret not mixing the families sooner.

My mom “met” my MIL at her funeral after 6 years of dating. Which made me sad

Mixing families can be stressful but it’s harder the longer you prolong it IMO

For context: I’m trying to get a sense for what is a “normal” level of involvement and family integration.

I personally only ever saw both sides of my family together in one place at birthdays for my siblings and I and the occasional Christmas, and the majority of my friends claim the same thing. My husband grew up with one set of grandparents on the other side of the world, so obviously no major mom/dad side integration in his childhood either.

Right now all of our family events are separate and we don’t have kids yet. I don’t mind our current set up. We tend to see my family more frequently because they live close by and we have a lot of fun together and genuinely enjoy hanging out. We see his family for holidays, and my husband dreads going there as it’s always dysfunctional. We try to plan neutral ground outings for better behaviour, but they tend to cancel on us for those.

The issue arises because my mother in law feels “excluded” from holidays that she does not even celebrate. She guilts and complains to my husband about this a lot without making any effort to form a bond with me or my family. She recently blew up at my husband over not getting an invite to my grandpa’s funeral when she hadn’t met him, didn’t even know his name, and it was an open casket service for immediate family and close friends only.

I genuinely have a hard time understanding if this is just a major cultural difference in defining family through obligation vs real connection, or if my MIL’s deeply rooted exclusion insecurity is driving this fantasy of wanting to be perfectly integrated into my family without even knowing them.

It honestly depends on family dynamics.
My husband and I no longer live near either set of parents but we used to live closer to his. I have a friend where the in-laws are great friends and do a lot together all the time (even without their kids present) and didn’t know each other before they started dating.
And I know some that have only met the other parents a few times. When my dad passed my in laws drove 8 hours each way and stayed in a hotel so they could attend his funeral and they’d only met him a few times. If we lived closer to both sets we’d probably do joint holidays but we’ve never all lived in the same state.
For reference we’re not super close with our parents. We chat on the onceish a week. So our relationship with them feels natural.

OP: I might be reading this wrong, but describing your MIL’s feelings as “deep rooted exclusion insecurity” suggests there’s already a lot of frustration there.

From the other side, I’ve seen how painful it can be for a parent to feel excluded from their adult child’s life. My brother is in the middle of something similar with my sister-in-law and my mom. My mom doesn’t need to be at everything. Sometimes she just appreciates the gesture of being invited.

Even if you know she won’t celebrate the holiday the same way (or at all), an invite can signal respect for the role she played in raising the person you love.

Sometimes family relationships run on small symbolic gestures like that. It might feel like an inconvenience, but to the other person it can mean you care or at least appreciate them.

Similar to you OP, my family is closer so we see them more. My MIL also has gotten mad about the imbalance of time we spend with her (though she’s never tried to muscle her way into my family’s funerals!?!). When we go to visit her we have to stay overnight so it is a bigger commitment but we do go quite often.

We do all holidays separately, the families don’t mix that well, it’s very stressful. We alternate years and one day I want to make it so we have a third year in the mix with NO family so we can just relax.

I set a boundary early on that I wasn’t going to organize both family social times so I do mine and he does his. Sometimes I think that means there are less plans on his side but meh. I think that’s how he likes it tbh.

You can’t make your MIL act in a more normal way so set your boundaries as much as you can and no you don’t have to mix her into your family if it’s gonna feel weird! My opinion 🤷‍♀️