hi starcat-
regarding your phone options, why not just drop him from your plan? i don't think that is vindictive at all. you've split up, he's moved out and it seems reasonable that you would no longer pay his phone.
also, i feel it communicates a clear message whilst continuing to support him in this way could send a conflicting message to him.
also, when i split from my abusive alcoholic, i found it useful to vary some of my patterns and habits. for example, lights in the house. normally, when i went out, i would turn off all the lights. i began leaving them on.
i also would leave my shoes in the stairwell. i began taking them in.
i also began taking different routes than usual. i didn't go any longer to the same pub. i switched hours i went to the grocery store.
since you've been living together, he will know your patterns and haunts. please consider switching things about for awhile, until things calm down.
you mentioned that there are a few doors to your apartment. perhaps start using a different one, and bracing a chair against the other ones. this way, you will have enough notice if he tries to enter.
i also took the step of alerting the neighbors to my situation, so that they could report any sitings to me. i also told them if they heard raised voices, to call the police immediately.
stay safe!