How Long Should A Man Stay In His Cave?

Hi John-

I have been in a relationship with an amazing man for about 7 months now. He's 27 and I'm his FIRST serious gf.

I found it hard to believe at first because he's been such a wonderful bf to me and totally knows what he's doing. In the past few months, I've experienced him "caving" and perhaps "rubber-banding". I can usually tell when it starts and know the steps I need to take when it happens, such as giving him space, leaving him alone, ...