Hi Sharee – thank you for your questions.
From the sounds of things, there might have been a bit of ‘male ego' bruising in relation to you knocking back his pick of the initial home to buy.
That's probably the instigator of perhaps a subtle lose of self confidence in the relationship. That's then a ‘fight or flight' scenario – and it's way way easier to take flight than to stand firm and sort that frigging weirdness out. Especially when the weirdness might be your own (his in this case)
I'd like to say here though that moving into a ‘let's fuck when I need you' relationship is something you should seriously consider NOT doing. It cheapens the wonderful person that you are and tells him that you have little value for the relationship.
Determine what it is that you do want in both a relationship as well as the ideal partner. Does he fall into the latter?
From all this, I've got a few questions for you though:
 Have you found him a little bit of a control person in the relationship?
 Has he actually ever really (I mean really) committed to both you and a long term relationship or just flossed around by giving potential signs that he is?
 Do have direct information that he can't live with people or is that something he's just told you?
Look forward to getting a bit more background information from you.