My boyfriend and I are both 32 years old.. We were dating for 5 years today and he still hasn't asked me to marry him.. help!

First, almost all US states have eliminated common law marriage. So I doubt if you can refer to him as a common law anything. Besides when common law marriage existed you had to be living with the person for x number of years.

So what do you need help with? Maybe its time to move on. Have you talked marriage at all?

Stop dating him. If you are living together move out or put him out, if you are having sex with him stop that.
Why would he want to get married?

You guys need to communicate, not speculate. Or shove things under the carpet.

Healthy and forward moving relationships are built on communication & goals together. Being on the same page, and working to understand each other's needs, and more.

Sounds like you all of sudden had a milestone he wasn't aware of. Or if he did, I don't know. Need more info.

Are you happy? Have been? All good otherwise?

5 years is a long time for two adults to be dating and there not be any mention of marriage or some understanding about it.
If he doesn't want marriage and you do you need to decide if you want to continue in a dating relationship.
Is he aware of your feelings?

"If he doesn't want marriage and you do you need to decide if you want to continue in a dating relationship."

That's it right there in a nutshell.

Why should he want to, What benefit is he going to get ?
You are living together, and most likely does not see a reason to.

So have you asked him about it ?

You obviously never talk about what's in the future for you both. Sitting for 5 years without even approaching the subject is unthinkable, or maybe you figure he can read your mind or something.

Why get married any way? What difference would it make to you? What would it change except for the insurance papers? Or tax filing status?

If things are great, why change them??

Life is too short & seems dating became very comfortable for both of you. If you want more out of life, take the high road, be strong & ditch that lazy guy. A real Man, a Man in love would have married you a long time ago. Personally, after wasting 3yrs on a relationship that was supposed to end in marital bliss will never do so again! Life is to short & far to precious. There are so many adventures to be lived and frankly; as long as your with "MR WRONG"... You'll never meet "MR RIGHT". He's out there, have faith! BTW: not a good idea to "move in" with any man until your married. So many people assume things will change after marriage, but it is what it is. There are plenty of opportunities through spending time & travel to get to know someone... but, like yourself & put yourself first