This thread is nuts. I feel like I've strayed into an alternate universe where Mumsnet doesn't exist and it's MILsnet all the way!
Just because OP's tone is defensive and snippy doesn't mean she's the horrible person PP are saying she is. It means she's pissed off.
Just because the MIL is widowed doesn't make her a saint.
OP says she's put up with years of digs from her MIL that infer she doesn't look after her DP properly and is a shit homemaker, which PP are choosing to ignore – OP knows her MIL better than any of us do.
OP did snap back at her MIL over the packed lunch and did make a comment that must've been hurtful, but after eight years of digs, she clearly has little patience where her MIL is concerned. Are you all saying hand on heart you've never made a bitchy comment in the heat of the moment?
DP clearly takes MIL's side every. single. time. and likes being babied by his mum. He is not wrong in wanting that kind of relationship, but he doesn't seem to care it is standing in the way of the two women in his life having a decent relationship. He's playing them off against each other.
Few women – and none I know – would welcome their DP going round to his mum's every. single. morning. No cosy lie-ins, no breakfast in bed, no spontaneous morning sex, no cup of tea and a chat before he goes to work every. single. day. No wonder OP's fed up!
It's unlikely he is going to change his routine when they have DC. If they have a daughter, his mother may well think she still ranks higher than her too in terms of female hierarchy in his life. How nice for his child.
Arguably, MIL has now resorted to emotional manipulation to get her way and drive a wedge between OP and her DP. Again, being widowed doesn't make her a saint.
OP, you could have 20+ more years of this. I'd walk.