My husband denied my Facebook friend request and blocked me

I haven't been on Facebook in years, but I recently I made a Facebook page to keep in touch with some friends who moved away. One of the first people I added was my husband.

I told him I was sending a friend request and he didn't say anything. Later on I couldn't find his request in my friend request box and I couldn't even find him on Facebook. I felt he blocked me so I made a throw away Facebook account and I was able to search him and everything. I'm heartbroken he blocked me.

I want to ask him why he blocked me on Facebook, but anytime I question him, he gets angry and says I'm not trusting him.

He has cheated in the past and we're working on things now. Things have been going well. He just upgraded my wedding band and he's been spending more time at home.

How do I approach this subject without him getting angry and us getting into an argument?

He told me before that I didn't trust him he was going to leave. I don't want him to leave but I also want to know why he blocked me on Facebook. It makes himself look suspicious even if he's not doing anything. Could he be cheating in a way?