Most Helpful Guy
Because he is smart? Maybe he knows that real and sustainable love has nothing to do with being married. And that being married almost always ends up really bad for men (it's still mostly the men who lose their money and have to pay for a very long time or their whole life for their ex-wifes. And even far worse: almost always the women gets custody for the children and the children taken from the men - this is really really horrible). And by statistics he knows that this marriage is highly probable to be divorced (and 70-80% of break-ups and divorces are initiated by females). So, boys, do not ever marry! It's a horrible deal for men and a really dangerous situation you put yourself in (in all other areas of life you would be classified insane to agree to such a destructive deal).
Most Helpful Girl
Why do you assume he has to propose or want to live with you? Lots of men and women are happy NOT to move in together or get married. Nowadays there are just as many, if not more, who prefer that. IF you are both financially stable you do not need someone to pay your bills for you, and it would not be very nice for someone to want to be with someone just for finances. Either he is the right guy or he is not, if he is then seeing him a lot without living together should be fine unless you were both planning to have children and live together as a family unit. That piece of paper you get when you marry does not mean much. I know lots of men who get married (or even engaged) and then carry on trying to date or sleep with other women. It rarely changes the way they see things or the way they behave. And there is just as much chance or more that they want to end the relationship or cheat later, it is no guarantee they belong to you or it will be forever. If they are not keen to marry and get nagged into it or do it to please you then the marriage starts off with a bad taste and goes downhill from there, much more likely to go wrong.