Somehow, some way, I suspect the commitment phobia here isn't entirely on your end.
The whole "I was going to ask and then you ticked me off" line is garbage, pure and simple. There is almost no couple on the planet that lives in perfect, serene harmony. It just doesn't happen. We're not built that way. We get along the majority of the time, but married or unmarried, we're going to do things that irritate the other person, accidentally or intentionally.
I don't recommend an ultimatum, but I do recommend a discussion. Ask him what he sees in the future, and how he really feels about marriage, and go from there.
yep. that line about it being your fault you're not married yet is horsepiles, sorry. hate it when guys deflect their crap onto you like it's your fault. eeeessssh so aggravating. i dunno, i know RP isn't a fan of ultimatums, but honestly, 5 years?? may be time for one in my opinion. what's going to happen if you try discussing it? maybe he'll get defensive again, aw gee, almost had a ring picked out but then you went and left the toilet seat down again. maybe he won't. but a talk of some sorts definitely needs to be had, and you need to be pretty firm, otherwise if you DO marry him, i suspect these issues won't stop.
Ever think that maybe you're scared because it's your intuition(or rather your "gut") telling you that he might not be the right person for you? Think about it -- you've invested 5 long years with someone who somehow still doesn't find you "suitable" enough to deserve a marriage proposal. Instead he tells you that he had intended to ask you but that you somehow managed to anger him yet again. Now think about that for a second -- even the healthiest of relationships include angry days/moments -- so all in all anger is unavoidable and something that every couple learns how to deal and cope with if they expect to remain together. So his excuses are either his way of avoiding/skirting the issue or perhaps a prolonged stalling tactic, but either way you're better off finding out sooner rather than later. Don't let him continue to waste your time if marriage is something you want, but it's not something that he's willing to contemplate even after 5 long years together. It's time you ask him for a frank discussion on the subject, and if you still don't get the answers you're looking for, whether it's wise to continue on with someone who through his own inaction has made himself clear on the subject of matrimony with you.