Been with DH nearly 25 years, we are born and bred in the south and when we first met he spoke like me.
After about 10 years he started dropping his t's (batteries are now ba'rries). A few years ago he started saying ain't 
But now he totally mispronounces words especially those with u in it.
Assume is now assoom.
Once he pronounce puberty as pooberty (he at least had the good grace to correct himself)
The G in long is now over pronounced as though he isn't a southerner.
There is now thurr.
I asked him gently tonight why he does he and got pissed of fans says I attack him about it.
But it annoys me, it's unattractive and cringey.
I know I'm being unreasonable. Tell me I am so I can feel guilty and get over myself.