It really depends on the couple, there’s no right or wrong. Personally I believe no matter how much you might feel part of your partner’s family, you’ll always be an outsider, and it’ll make your head spin how fast they’ll close ranks on you if the relationship goes south (even if you’re the wronged party). So as much as I enjoy spending time with OH’s family, I bear in mind i’m only there due to my role as OH’s partner and don’t get too comfortable or take it as a given.
I’d do anything to care for OH’s family in the same way as I would for mine (the ones I’m close to and who respect and care for me too), I think a nice thing about relationships i caring for each other’s family. It’s an expression of your love for your partner and acceptance of them and the people they love. But if it becomes taken for granted or one sided then it stops.
Some couples really believe in the idea that a relationship is two families coming together, whereas others are far more individualistic and believe it’s about them as a couple only and who they’re related to should have no bearing on the relationship. No right or wrong.
Your situation sounds perfectly normal, couples don’t have to be joined at a hip, if you’re happy with the amount of time he spends with your family and he is too then that’s great, chances are your family either have a bit of an old fashioned view that couples ought to always be together, or they just say it because it’s something to say, small talk, it’s quickly visible he isn’t there and a mutual topic to mention.
Are they just saying stuff like ‘no John today? What’s he up to?’ or more pointed comments like ‘he never seems to come along, has he got something better to do?’
are you genuinely fine with it or do you feel a bit embarrassed by him not attending? And is that because you wish he would but don’t feel you have the right to ask? Or more because you feel it reflects poorly on you in front of family?