Husband wants divorce and I have no idea why! Help!?

Alright so my husband works 2 weeks on and 2 weeks off in another province, so he flys back and forth (camp job no females all males). He left last Saturday and when he left everything was great we were happy in love etc and everything was perfect. Wednesday morning he texted me and said he loved me and he'd talk to me after work... then he emailed me that night and said when he got home he was filing for a divorce that he wasn't happy and that he was relieved to be away from me. I WAS DUMBFOUNDED! I know 100% he is happy because I have seen him unhappy before and he was not in anyway. He has not spoke to me since and said he would not be talking to me until he was home and then he would speak to me about money and visitations with our 11 month old son. I am so confused and I don't know what to think! Now, everytime we have issues which we have over the years he always runs from them rather then faces them, and always starts talking to his ex from when he was 16... They both say they are only friends and I haven't seen any evidence otherwise and she always has a boyfriend when they are speaking... He started calling and texting her on Friday (I can see everything he does on his cell phone through the carriers website). So I flipped out and shut his phone off when I found out Yesterday. He won't even talk to me but talks away to this floosy.. doesn't even bother to ask me how our son is or nothing! SO I texted her which she knows I would do because everytime something happens I text her, usually we're pretty civil and she tells me what he says etc.. this time she wasn't answering because he did this in August and was lying to her about being back with me etc and she was fed up with hiim lying and didn't want to be his friend anymore, so I figured that was why she wasn't answering me... So I Started calling her names and telling her she was ugly etc, normal woman cattyness! THEN SHE COMES TO MY HOUSE this crazy comes to my house where I am alone with my son and she bangs on my door telling me I should come out etc... I called the cops to report harment. I don't know what makes her think it was okay to come to my house because I'd liek to know what her plan was if I answered the door with an infant sitting on my hip... Anyways, my husband knows what happened even though I shut off his phone because he bought a calling card and called his mother, who told him, and she said he acted as though he already knew, so he obviously also called the floosy on the calling card. UNBELIEVABLE RIGHT? Still talking to this person who came to his home where his wife and baby son are haring them... pretty much talking to her saying it's alright she did that and doesn't even CALL ME! SO that's my situation.. He comes home next Monday for 2 weeks and I don't even want to think about what's going to happen. He likes to take breaks from reality it seems and live like a teenager while he can. How can I make him realize this time he has to win me back? That I have a backbone now and it's NOT OKAY that he is doing this to us again? I love him more than anything even though this is all going on he is still my husband and father of my child... I need to make him know that I'm not here like a sitting duck waiting for his return again and I think the first step was me shutting off his cell phone. What else can I do? What do I do when he does call or show up at our family home? Help I want my husband back but I don't want to be the one groveling at his feet when he is the one in the wrong!!! Sorry if this is long/all over the place but I tried my best to explain the situation!