YOu should be feeding 2-3 pellets (pre soaked before feeding) twice daily, with one whole day of a week dedicated to a "fasting day".
Bettas are opportunistic feeders. Their wild cousins honestly never know when their next meal is, so they gorge themselves. I guess it stayed with them all the way through domestication. Wheter or not they are hungry, bettas will search for food and beg. But don't worry, so long as you are feeding correctly, he should be fine.
He is bloated, I would fast him a day then decrease to two pellets twice daily.