Married sex life issues

Throwaway for obvious reasons,

On the surface my life is pretty great, I have a good job, wife, 2 kids, home etc.

My wife and I have been together for 12 years and our sex life has been good until around 2 years ago. After our last child was born my wife’s sex drive has massively dropped, she refuses to give blowjobs as ‘it’s not something a mom does’. Sex has gone down to once every 2-3 weeks and the last time we did the deed she tapped out saying she was too sore.

Before some people jump in I love giving my wife pleasure, I have no issues finishing her before myself.

Basically in general my life is good and my wife and I get along great except for sex. I’m really not sure what to do about this as I don’t want to be sexually frustrated the rest of my life, but I also don’t want to blow up my family.

Any advice, tips or suggestions?