I think the first thing to point out is that you are not actually talking about the future with your boyfriend. You are making assumptions and dropping hints.
It's certainly acceptable and generally a good idea to discuss the future with a long term SO. That means being direct - "Do you see us getting married some day?" (if yes) "When do you see that happening?" "Where do you see us in two years?, Five?" "Do you want kids?" "When?" If he says he wants to marry you, some day, then "Where does buying a house with your friend fit into this."
But what you are currently doing is basically assuming that you guys are going to get married and have kids, and dropping PA hints about it.
And I'm sorry, but from everything you've said it sounds like you and your BF are on totally different tracks. You're thinking of nesting, picturing your wedding, and kids and life together. He sounds, to put it bluntly, like he enjoys his relationship with you, but currently has absolutely zero intention of getting married or having kids with you or anyone else in the foreseeable future. If he's talking about buying a house with a friend, ie, a very, very major purchase and life decision that doesn't involve you, that just drives home the fact.
For what it's worth, talking about the future only scares guys off when you're jumping the gun (talking about kids names on the third date, say), or when they aren't interested in settling down. For guys who are ready to settle down, it's not a problem. After my husband and I had been dating for a less than a year but before we were engaged, we had seriously discussed things like kids, jobs, what country we'd live in and things like that, so it was clear we were on the same page.
From your perspective, you face a difficult but common decision. Are you happy to stay with your BF, *as things are* with no guarantee of marrying, living together, or having children? Keep in mind that you could wait for him for ten years, and then find out that he still doesn't want to get married or have kids. If the answer is yes, then you're okay. If the answer is no, then you *will* be okay, but it'll be painful for a while, as you move on with your life.
But it's really important not to get caught in a holding pattern, with your life in idle waiting for something that someone else has to give you. Whatever you do, live your life fully. This is the time in your life when you can try new jobs or cities, travel, take up new hobbies and make new friends. If you spend it waiting for 'someday when he'll marry me' you can waste a lot of time and opportunity, and regret it later.