I would say no.
If you tell him you have a walk date set at some point in the future, it will hang over him kind of like a dare or a threat and that’s not the message you want to send.
I think if you’re already emotionally at a point where you’re thinking in terms of a walk date, the walk date should be now. If he hadn’t told you two full years ago that he could see you guys being married by now, and if you didn’t have your heart set on being married, my advice would be different. But the words came out of his own mouth, and he himself set this deadline.
I am not suggesting you break up with him without talking to him first. But I don’t see the point in giving him the opportunity to waste even more of your time, if you’re already thinking of setting a walk date. If he’s really going to flake out on you and not stick to his word, why not find out now vs. six months, a year or two years from now?
Under no circumstances would I tell him what to do. (That’s his job!) I would rather ASK him what his intentions are. This is how I would pose it: “Sweetie, I love you with all of my heart. The past XX years together have been the best years of my life. I want nothing more in the world than to spend the rest of my life with you. But marriage is one of my goals in life, and I’ve reached a point where I can no longer stay in a relationship indefinitely without knowing where this is going, and when. I need you to tell me what your plans are for us.”
Then sit back and listen to what he says, as well as what he doesn’t say. If he suggests getting married in the near or reasonable future, then great.
But if he flim flams around and doesn’t give much of an answer, or if he says that maybe he’ll be ready at some far off point in the future that is not acceptable to you, then bingo, you’ve just gotten your answer and avoided wasting months or years of your life in a relationship that is not meeting your needs or aligned with your goals in life. In that case I would pull back from the relationship and start taking steps to reinvent your life in a way that you can pursue your goals and dreams.
After two years, you deserve an answer NOW, not six months or a year from now. He owes you at least that.
Good luck with whatever you decide to do!