You can *talk* through disagreements; he can stay without getting overly emotional or wanting to be right or getting his way all the time. The same applies to you. You both should be looking for win-win solutions where possible. No yelling, name-calling or hitting!
Both of you need to take the committment seriously. Don't assume because he's willing to get married to you that he's committing or will stay committed. Talk about what that means to each of you so you know.
Talk about finances. How does he handle his finances? Does he live within his means and save for the future or is he an impulsive spender? Is he willing to work for what he wants? Is he willing to improve himself? You don't want a moocher who will dump all the responsibilities and work on you.
Is he overly obsessed with anything -- sports, work, his family-of-origin? Can he say 'yes' as well as 'no' to others (like his mother) with equal ease, or is he a people-pleaser?
Do you know the difference between confidence and arrogance? If not, learn what they are and how to tell the difference. You want a confident man, not an arrogant one.
http://womanitely.com/ways-difference-arrogant-confident/
Do you both have similar values and want the same kind of lifestyle? Kids or no kids? City or country living? Laissez-faire, v. non-stop go-getter? Religion? Those differences really start to chafe over time.
Does he ever lie to others in your presence or is he a man of integrity? If it's easy for him to lie, watch out. Don't assume he won't do it to you.