When is enough finally enough? 

Are you, in fact, in the process of divorce? 

My ex and I had a similiar problem.  I was suffereing from horrible insomnia and depression caused by emotional abandonment.  Now, he didn't accost me every morning, but, he did occassionally try.  In fact, there were numerous occassions where he had sex with me while I was asleep.  They call that spousal rape. 

I tried to talk to him about showing me affection...for affection's sake.  Sounds like your ex doesn't understand that concept, either.  On the other hand, staying up all night doesn't help the situation.  Go to bed at the same time.  If you can't sleep, then get up after he's gone to sleep.  However, if you have already decided to divorce and aren't changing your mind, then, sleep somewhere else.  You are only sending him mixed signals.

Perhaps this is over-simplifying but:

He doesn't communicate because he's angry with you about never having sex.  You don't want to have sex because he never communicates.  Both of you are feeling deprived, and at this point neither of you is willing to "give" for fear it won't be reciprocated.

If you don't go to bed when he does, then please tell me when he is "allowed" to initiate sex?  You're up half the night, why? Waiting for him to go to sleep?  And then when he wakes up and realizes you've finally come to bed, well yes he's going to be horny because you never have sex.

I get it, you want him to romance you.  But he's not going to spend half the night wooing you when he thinks he's going to get rejected anyway.  One of you has to break this downward spiral.  Before you decide to get a lawyer, try going to bed at the same time for a change.

You have a lot going on, in my opinion. If you are getting a divorce, I have to ask, why is sex even on the table? On one hand, he shouldn't expect it. On the other, you shouldn't expect much acknowledgement either. First, whatever you are doing isn't working, so do something different. The result may change. If the result you desire happens, you know what to do. If not, try something else. You can always sleep somewhere else, the couch, an air mattress, or if you do actually want a relationship with him, try showing him affection at a time of day you feel more available. It isn't just up to the male to start things. I guess I am at a loss, but first you need to decide if you even want a relationship. If not, you cannot expect to share a bed and live together as husband and wife until the divorce is final. You may need to move to the couch. That said, honestly, I wouldn't be thrilled with a man who could care less about what I wanted sexually. And if I expressed distress as you do and the guy responded like your spouse, I'd know I could do better. I don't think many men would find that behavior acceptable if the woman in question was their daughter, but I could be wrong. My ex has many faults, but if anyone ever treated our daughter as you describe, I know he'd be more than upset. He'd flip if a guy treated me like that, and he left me.