What a douchetard thing to say!

I'm sure he has good qualities or you wouldn't otherwise be with him, but calling you a liability was a d*ck move and makes him look like an a.s.s.
I hope he realizes this sooner than later.
Marriage is a fundamental topic for any couple, and differing views either lead to misery or is essentially a deal breaker.
Find out when he knew about his aversion to marriage. If it was before dating you, then he kept quiet about something pertinent too, and will give you firmer footing regarding hiding your dx. Thus providing even grounds for both of you when you broach this liability topic.
*ugh the word leaves a nasty taste in my mouth
I mean, you can't string along someone you profess to love indefinitely. He should've been upfront about his view in order for you to make an informed decision about investing so much into something that essentially leads nowhere if marriage is your end goal.
I hope you 2 work things out or you run like hell if he stands firm by his "liability" stance.
Liability my a.s.s!!!!