I know these feelings well. I have had two major relationships in my life, and both told me I seemed to not want to talk about my feelings much, even though other people seem to think I wear my heart on my sleeve. Seems I can talk to strangers about anything, but as I get closer to people, then I raise shields. Guess that's how it goes.
My earliest memories were my father beating the crap out of my mother. Then I remember how the damage she had taken played itself out in alcoholism. So part of me doesn't want anyone that close to me, because I fear being hurt, and I fear hurting others. I'm over 50 and I'm not violent, never have been, but I know there's some deep seated brokenness within.