Online dating is like a sweet shop, there is a tendency to look at what you've got now, and keep looking around to see if there is anything better, because it gets addictive, checking for messages, winks, new profiles etc.
But, if you haven't met Gemini yet, he's going to be not putting all his eggs in one basket either, he'll probably be talking to several people, and he's allowed to do that, it's natural (as far as anything online can be natural).
Even if you have met him, (I don't know if you've had a date already?) he's still probably going to be chatting to other people, and you're allowed to do that too. It's par for the course, otherwise you get all overinvested in one person, meet them, get disappointed, and it's back to the drawing board...
I've seen many posts on these threads where a woman has got weirded out by some bloke who says he wants to go exclusive after only one date, and a couple who said they'd stop looking for other people even before they'd met. That's a bit over the top.
Plus, he may have been chatting to friends on whatsapp, or just not have switched it off.. Trying to guess what's going on at this stage is the path to madness.