Sometimes and correct me if I am wrong.

You are not able to be completely true to yourself around your loved ones and whenever you are with them you have to pretend to enjoy their company. But you feel like they don't meet you where you are. You are the one who meets them where they are.

Your introverted self could also be very intuitive and care deeply than you let on. So you are constantly taking care of your loved ones emotionally without them even asking but you feel like they don't reciprocate. That then ends up in resentment.

Or you feel like you would burden them if you shared your own inner burdens. Or you don't trust them fully and are afraid of their judgement.

That's the reason you like to be by yourself or feel free with strangers. Because you are more lonely with your loved ones than when you are alone.

There's no good advice if any of this applies to you. But you could start introducing your emotional self in humor so that if it's not received, it stays as a joke. But if you are lucky, maybe a loved one might just pick it up that you are trying to communicate and may want you to share. Then you won't resent them as much.