Introvert Boyfriend

Hey everyone! So my boyfriend is a MASSIVE introvert and will sometimes isolate for a few days. It’s normal for us to not talk for 2-4 days at a time. It’s been like this for our entire relationship (5 months) However, we hadn’t seen each other for over a month up until last week, because of a COVID scare. We got to reconnect and it was amazing but now he’s disappeared again and it just feels personal since we have had plenty of time apart. I know he’s not cheating, but I’m worried that he isn’t as serious in the relationship as I am...words of advice?