Unusual behavior...venting

How do you handle your SO behavior that may seem a little off?

Example: my SO always tells me when he's about to head out and leave the house to where ever . We never had a problem with that. But recently he's been a bit distant with me arguing more with me and when I ask a simple question like "how's your day or what you've been up to?" Its a problem with me being "nosey" I'm not allowed to touch his phone without permission and if I grab it it's always an argument about me not trusting him but truth is I NEVER even freaking lay my eyes on his phone it's that deep. . I hate arguing and he's not an approachable person . He just up and left and I asked him witha little curiousity where he was going and he responds "does it matter ? I dont have to tell you and its none of your business don't come looking for me.." I seriously feel like crying . We were just having a good day. I can't help it honestly and it's not THAT easy to just up and walk . I'm due with our first in a couple of months and I'm afraid that this is what I'll go throw after the baby is born. I highly doubt that since the baby is almost ready to be born he's acting like that so that's just bull shxt..