Hi, hope you have a local breastfeeding support group or service you can call to work this out.
some things that pop in to my head to try are-
try putting him on that boob midway though feeding on the other boob- a cheeky swap .
try him with that boob first or second… whichever is the opposite of what you are doing regularly. Mix it up. See what works .
try that boob when he is sleepy/dreamfeeding. he might not notice as much.
try that boob when he is happy/grumpy … hungry/not hungry. Tired/alert.. This may give clues as to why he’s annoyed at that boob.
try different positions- snuggling in bed and laying down for him to feed when laying next to you in that boob may help as he could just be struggling with the changes in his positioning as he grows. try feeding standing up or in a sling. See if anything helps or hinders position wise.
babies can be sensitive to changes in let down that we don’t notice, it may be that the let down is stronger / weaker in this boob at the moment for whatever reason.
if he is coming off at the point of let down it could be that it’s faster / stronger than the other one.. try pumping a bit first then popping him on after initial let down , to see if that’s better? He may prefer the more reliable and predictable flow if the other boob at the moment.
equally Maybe it’s not coming out fast enough / as fast as the other one , so he is cross at that boob and prefers the other one ?
If he is favouring the other one your supply may be less in the less favoured boob, so you could try pumping from this one a bit if he refuses it at feed time to keep the supply up and make sure this doesn’t become a vicious cycle.
Sorry , I feel like I’ve given lots of conflicting options but often it’s a trial and error situation with breastfeeding and these things change and change back and change again! ultimately , you might never know why he’s doing this, but it will likely pass and something new will happen to have you scratching your head.
well done , sounds like you are doing amazingly well with your BF journey . Dont be disheartened, this doesnt mean its not working or is going to mean the end of BF if you dont want it to be …likely just a little bump in the road to work out xx