I have a daughter (15) who I'll call M for this. My DP who I married about 5 years ago has a daughter (16) who we'll call C. Both girls get along really well, can't be separated mostly. DP and M have always gotten along considering C is mainly living at her other parent's house and only comes to ours maybe once a month. However, since DP and M rarely argue it means when they do it's BIG. It makes me so upset to see them like this as both have a very argumentative side. C on the other hand barely ever argues with DP - she's more shy/reserved. M has always been confident and extroverted and she's never afraid to speak her own mind and be herself which i've encouraged. Honestly, it's like two flames attacking each other and the fire just gets bigger and bigger until M is forced to apologise by DP.
DP has been so so helpful with M as they've known each other for 13 years now but M will see her biological dad a few times a month who are also very close.
I think it's a real problem that they may be too close in the sense that M might feel as if DP is trying to replace her dad (he does say that he's not a lot of the time if it does come up in conversation) but what do you think? Is it literally just two short tempered people having arguments and i'm being dramatic??
Just to explain a very recent argument to give you an idea: we had a family meeting to decide what we're doing tmrw as we're on holiday (all 4 of us) and we agreed on a small village to get lunch. DP suggested we wake up at 7am to get to the village by 9am but M did not take this lightly and suggested we wake up at 9am and get to the village by 11am. C stayed quiet (obviously) and so did I so it was back and forth. DP was very dismissive of M and shut her down whenever she tried to speak and he does this a lot. He has a sort of 'i'm the male, i'm the boss' mindset. M told him to shut up which DP told her off a lot for and i'm so worried that this relationship between them is getting really toxic, it's the smallest things that set them both off which ruins the whole miid for everyone else.
Anyway, DP said to M that she's just trying to show off to everyone and called her cocky and rude. And this is all whilst they're SHOUTING at each other.
It's become very awkward for everyone whenever this happens and it's getting way more common now since M has basically become an only child and I think that's difficult for her.
Please reassure me that this is normal or just call either one of them out, i don't care who i just need this to stop!!