I have been with my partner for around a year and I have two children from a previous relationship. Current DP has no kids and little experience of kids.
Anyway I've noticed that he has little regard for their safety. For instance when we took them to the park he was pushing my 5 year old on the swing (who has NO sense of danger) and he was pushing him so high that the swing was almost tipping upside down, the chains were actually going slack at his highest point as he was almost upside down. I kept telling him to stop but because ds was laughing/screaming DP kept laughing and continued to do it. DS1 (sensitive child) was screaming at him to stop saying hsi brother was going to fall and even another woman came across and told him that she'd seen kids fall off the swings at that height as she had seen me getting agitated. He finally stopped and later apologised but why would he do that? is it lack of experience or something more sinister?
Other times he's flicked bleach water in DS's face (later saying he didnt know it had bleach in but it was water out of a bucket, surely he knew it wasn't exactly clean?) and he sprayed suncream all over his clothes whilst at the beach in summer for a laugh but it all stained.
He just seems to do dangerous stuff to them all the time and acts as if he's just trying to make them laugh but it all seems so clumsy I cant work out whether he genuinly doesnt realise?