My toddler is 2y3m and my baby is almost 3m, both boys - I researched how to introduce them and how to foster a good relationship between them and while my toddler seems to love the baby and is always talking about him / introducing him to literally anyone we walk past at the park etc, he hits/bites/kicks the baby every single day.
He can be gentle with him for 30 seconds or so (kissing and stroking and tickling the baby), then he lashes out, and when we try to redirect the toddler to another activity and take the baby away before the toddler lashes out, he grabs onto baby's face/head/arms and squeezes him really hard.
He's done this consistently for 12 weeks now and I'm getting worried that things aren't improving. Even more worried after reading this post and seeing that everyone else's toddlers seem to only be hurting the baby by accident or on a rare occasion! We've tried everything mentioned above plus teaching the toddler about different emotions and how to handle those appropriately, and he seems to understand them but just can't action them when I assume his jealousy towards the baby just overcomes him, which causes him to lash out.
My toddler was not at all aggressive before baby arrived, he had never hit, bit, pushed or kicked another child, he is a very sweet, thoughtful and affectionate little boy, so this behaviour towards our new baby was a huge shock. The toddler would cuddle my bump everyday when I was pregnant, asked to "see baby" constantly and liked to fall asleep lying on my pregnant belly. I don't understand how we're now in a place where I can't enjoy the days I have both kids on my own at all because I'm anxious about their interactions!
It would be great to know how things turned out when their kids grew up if anyone has had a similar experience to this!
OP I've been reading the book Peaceful Parents Happy Siblings and it's great, all makes sense on paper - I just haven't seen the results yet. Hoping it will help my toddler get there eventually though,