My 6 month old has recently decided to not drink expressed breast milk from the bottle, only formula. He will however nurse okay in the evenings. I work, so exclusively breastfeeding is not an option. I’m not sure what to do.

Just some info, the milk he’s refusing hasn’t been stored in the freezer so I don’t think it’s a lipase issue...? It is safely stored/refrigerated. We’ve been giving him one bottle of formula/day for the past couple of months b/c I couldn’t keep up with his demand. We’ve tried 50/50 breast milk/formula but he isn’t a fan of that combination…so I guess we will try 20/80…

Any tips/suggestions?