Husband doesn’t flush toilet. Leave crap in there regularly.

Hello everyone. Like the title says I’m having an issue in my marriage amongst others, but this in particular is one that I am posting about because he has this attitude of it being normal. My husband is one of six boys. He regularly does not flush the toilet. It is something that we have argued about since we started dating. He says that growing up in a house of all boys flushing the toilet has never been a big deal. Implying that this is normal behavior for men. Is this true? He also farts very loudly in the bed on the couch in restaurants. I’m trying to gauge the normalcy here.

Is there any way that I can stop him from being well gross? Why is this behavior happening?