I think it should be his choice, and of course, the two of you discussing things is a good idea. I think it's great that he did seem to agree eating meat, or at least what happens to the animals before and during the process, is wrong.
I recently met the husband of an old friend of mine. This man does eat meat, but during our discussion, he commended me for not eating meat, and he said, "I eat meat, but I do not agree with the inhumane way animals are raised, treated, and killed for the food I eat. I wish I could do more about that - I absolutely disagree and hate it." I was so taken aback by his opinion and realized that he did care, even if he can't or won't stop eating meat. It's enough for me that he has some guilt or rather a conscience about it.
Just be honest in your relationship and things will be fine. I don't think it's wrong to ask him to consider some form of vegetarianism, just to think about it. But, if he honestly thinks about and says no, it'll be your choice after that to decide what steps to take. I don't think it's ethical to end a relationship over this issue, especially if there really is love and true friendship there. As long as he accepts your choices and accepts you as you are, so should you accept him. Now if he starts belittling you, badgering or making fun of you, that'd be different, as it should be for him if you started nagging him to quit eating meat.