I try as best I can to anticipate when and where I'll get angry and visualize it ahead of time to kind of desensitize myself.
I find this very helpful in situations I know will lead to an outburst. Traffic, the supermarket, being in the company of certain people, etc.
The big challenge for me comes in on the real reactionary stuff, and for me it's most often unimportant things like a football game I'm watching or some video game I'm playing. In those moments I've tried to slowly change my knee-jerk reaction from throw/punch/hit/hurt to think first. Always think first. When I'm able, it shows me that most of what I'm about to flip out over is not worth the stress to me or my wife.
Also consistently debriefing after a flip out helps me gather info for the next one. Reflecting back on my failures and what went wrong, also the times I've upset someone I love by not controlling myself.
I find I cannot be motivated by self-improvement. I can only improve to benefit someone I care for. So I do it for my wife and my marriage because that's what's really important to me.
If the Bible is your thing, then I guess that someone would be Christ. Not wanting to upset Him.