Be prepared: when you get into a relationship with someone, their family and loved ones are also part of the deal. This is why it is worthwhile to consider how you feel about spending time with these people in the amounts that your partner expects.
Families are far from perfect. Every one has its quirks. And when you grow up in one, those quirks seem “normal”. Coming in as an outsider though, it may be shocking to see the norms your partner has acquired. And tempting to point them all out! Don’t do this, resist the urge! Family is sacred, for better or worse. You can’t make fun of it, unless they do so first and even then you need to tread lightly. Ever crossed that line, getting caught up in the banter and taking the joke a step too far? Yeah, don’t do that with somebody’s mom, dad or crazy aunt Louise. There’s nothing to be gained and often, no coming back from it.
People make different decisions for themselves about what they are willing to tolerate for the sake of maintaining their family connection. Its an individual thing. You need to allow your partner to do that and not judge them for it. Or make ultimatums. This is not a “it’s me or them type” of situation. To force this kind of choice is unfair and unloving to your partner who is caught in the middle and struggling to make both you and their family happy. It is best if you accept that your partner and their family are a package deal and not expect any of that to change to suit you. Your partner gets to lead on this one.
That being said, don’t stay with someone if you really can’t stand their family (or worse) and they think they are great and want to have dinner together every Sunday night. You might be thinking that you can simply duck out of those events or keep contact to a minimum, but then you would be missing the whole point. Your partner loves both of you and wants you to connect on some level. If you can’t do that with an open heart, patience and the ability to keep your unkind thoughts to yourself about Uncle Joe’s shady business deals during family gatherings, then maybe you should seek a better fit. Particularly if you are already thinking that you wouldn’t want children of yours to grow up around these people. Your partner is going to feel that tension no matter how much you try to hide it. You don’t have to be best friends with the family, but if you can’t accept and get along with them peacefully for the most part, that is a bad sign. Continuing on when you are poorly matched with your partner in this way is serving no one. It is a recipe for ongoing discord, best avoided.