A couple of things. Why just mammals? Why not birds, too? Also, you can get humanely treated meat. There are farms all over the country that raise animals the right way and sell meat. Why did this turn you towards just not eating meat rather than just getting humanely treated meat (and not supporting the industry that voted against this)?
Note: I'm not saying you should keep eating meat. I'm just curious about some things. If you choose not to eat meat anymore, more power to you.
As I said earlier in the thread, free-range meat is readily available. I can't get it at the nearest grocery, but I don't have to go too far. However, it's more expensive, and I just don't think it's worth the extra expense. John's still eating beef, though, and if he wants pork, I'll cook that for him.
I'm aware that poultry aren't generally humanely treated, either, but one thing at a time. I also haven't ruled out eating buffalo or game meat, and if I visit someone's house and they're serving ham, I'll probably go ahead and eat it. It's a matter of what I'm comfortable with. I'm not comfortable being a vegetarian, but I'm not comfortable eating commercially-raised meat, either. And I'm not comfortable making an issue of it with my hosts, so if I can easily avoid it -- like by eating salad instead -- I will; if I can't comfortably avoid it, I won't.
Honestly, I'm not entirely comfortable with eating any kind of flesh anymore, but I don't think it's a good idea to try to change my habits too radically all at once. I gave up veal many years ago, and sometimes I still think it would be nice to have some veal, but it's not a big issue. I think if I gave up all flesh at once it would be a big issue, and I probably wouldn't stick with it. We gave up all but free-range meat some time back, but as our expenses kept going up and our income didn't, we started to find it prohibitively expensive, and went back to industrial meat.
I've gradually introduced more vegetables into my diet; sometimes I might have a large serving of cauliflower as the main dish and a small serving of meat as a side dish, for instance, instead of having a lot of meat and potatoes and a small serving of cauliflower. But I'm working within my comfort level and also within John's. The more I change my diet without changing his, the more complicated meal preparation is, and the less I feel like we're sharing a meal. Right now the differences aren't too great. We basically eat the same thing, but he has one extra dish, or else I just cook myself a piece of chicken at the same time as I cook his beef.
Another thing is that I've been making some changes to my diet to try to lose weight, and changes I've already made make new changes easier. I've cut some things out because the calorie load is, in my judgment, too great for the nutritional value or satisfaction I get out of it. For instance, hot dogs and sausage are out. It's always been my habit to cook bacon, corned beef, or sausage with breakfast, or fried bologna once in a while. I had changed to cooking only Canadian bacon with breakfast because the balance of calories to nutrition and satisfaction was better. So now for breakfast, it's just a question of dropping the Canadian bacon. It's not as big a change as giving up sausage and gravy and bacon and corned beef and fried bologna all at once, because I had already moved away from those things, and have even started thinking of them as kind of unwholesome. That was a bit of an adjustment, but I've already made it, so this next step isn't as big a deal as it would have been.
And John loves cheese; if I make him some grits and throw shredded cheese all over his grits and eggs, he hardly even notices there's no meat.
Actually, I'm about ready to go pescatarian, but I have two reservations: I'm concerned about getting too much mercury in my diet, and John just doesn't like fish as much as I do. I'm bringing him along slowly. He's eating fish once or twice a week, and shrimp once or twice a week, along with more chicken and turkey. And he was more than willing to give up eating ground beef four times a week if it meant he could have a small steak on the weekend.