Is it okay to ask my boyfriend to send me his share of the dinner payment?

We have been together 6 months. Usually I send my shsre of our dinner through Paypal. He suggested I do that once and we made it a routine. This time around I paid with my card. He didn't offer to pay his share or send it to me on Paypal. I'm worried he thinks I treated him. How do I ask without making it awkward? Would it be best to just let him pay the next meal?
Is it okay to ask my boyfriend to send me his share of the dinner payment?
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