A Waste of Time?

The first time my BD cheated on me was in 07 when I was pregnant with our second child.. I broke it off but quickly forgave him when he came crying back to me.. I thought it was a one-time mistake (like he said).  I was wrong.. A few months later he cheated again and carried on a relationship for two months.. Then he deployed and I gave birth and he begged for forgiveness again.. I convinced myself that I should take him back because I was still in love, our kids needed their dad, and BD needed me to be there for him while deployed.... So I stuck it out. After a year in Iraq (yes I waited for that a**hole for A YEAR!!!) he came back and things were great for the first month, besides the PTSD.  He was very moody, talked about death and killing, was paranoid of large crowds, couldnt sleep at night, etc.  After the first month he started drinking A LOT, going out to bars & clubs with Army buddies, getting into police chases on his motorcycle, being verbally abusive, spent our entire savings, even robbed a guy at gunpoint... INSANE!  Then he had a one-night stand, but convinced me it was nothing, that he was drunk and messed up, blah blah blah... He promised to get help and went to a therapist.  He was prescribed ambien and after 2 sessions quit going because he said it was too uncomfortable to talk to a stranger.  A few months later he started another relationship and I was done with him... I filed for divorce, custody, child support, and spousal support.  I got a job and started dating a little.  I had lots of fun with my friends and even took a trip to Vegas.. I was on the right track.  Meanwhile, a few of my friends were going through divorce as well, some of them also Army and having similar issues.  BD's realationship lasted 4 months.  I didnt care.. I had let go.. Then that crazy dude at Fort Hood went on a shooting rampage (NOV 2009) and BD called saying he was on post on lockdown.. I was watching on the news while talking to him .. I was SOOOO worried!  We told eachother we loved eachother and we were sorry and decided to work it out.. The OW went back to Houston and BD and I made up.  I had already moved back to CA (from TX) and he came here on leave right away and things were awesome..  But as soon as it was time to leave he started a fight (like he always does when its time to leave) and we stopped talking for a couple months.. I lost my job and got depressed.  He called apoligizing again and came out on leave again and things were great again.  Meanwhile, all my friends who were going through divorce had started to finalize things and get new boyfriends..  Two weeks after BD was here, he left for Iraq again.  That was 2010 and we were both wishy-washy about whether or not we should stay together.  I decided to be there for him but just as friends..  Another deployment, another year.. I didnt date because I felt it wrong to do while he is in Iraq.. He came home on leave in the summer and was crazier than before.. I'm sure he was on steroids.. He even choked me by accident (yeah right).. We fought the whole time.. I thought it should have been a happy time but no, he was very moody and a total jerk.. I was glad when he left, but extremely depressed because of how bad the visit went.. I got a therapist and got medication.. Helped a little, but I ended up having a bad breakdown and wanted to die, so I quit the medication and after 3 months of therapy, I quit the therapist... Then in August the deployment ended and BD went on leave (in Sept) and told me he was going to Florida with an Army buddy for 2 weeks and then coming to visit us for 2 weeks.. Our plan was to just be friends and get along for the kids.. The first day he was here, he started the manipulation.. Begged for me to keep him, cried, made me feel sorry for him.. STUPID ME, I took him back... We had an amazing visit... We did things with the kids, had lots of fun, went out together, etc. Not one fight... 2 days before he was to leave back to TX, I was sitting on the back porch thinking to myself "Wow, are we really going to make it an entire visit without fighting?" Right then, BD came home from visiting his dad and said we need to talk.. I got a sinking feeling and told him "I knew you were gonna come up with some reason to leave on a bad note"  He told me that the 2 weeks he spen in FL was really to visit his new GF that he met on Facebook and that she had just called him (after seeing pics of me & him on FB) claiming she is pregnant by him and he said he was going to be with her. He said she had been staying with him since August... I was so pissed, I left and stayed gone for the last 2 days he was here.. I thought about killing him.. The last thing I said to him before he left was that I hate him and I hope his plane crashes... I havnt talked to him since (Oct30).. He's called but I let the kids answer and as soon as he asks for me I hang up.. I feel like I wasted so much time with him!!!  Now, I look at my friends who filed divorce in 2009 like I did, and they are all in new relationships and happy.. I am in the same place I was 2 years ago.. Feeling totally crappy and depressed, no job, no money, no man, lonely, angry... Why did I let myself get off the right track???  The only thing I accomplished since we first broke up is that I went back to school and am getting closer to finishing... Other than that, I feel like a total loser IDIOT... I regret taking him back so many times.. I feel so dumb.. I have no self esteem due to the cheating and verbal abuse.. I'm SOOOO frustrated with myself!!!  If only I had stayed away from him I would be at the place in life my friends are.. Now I have to start all over again.....  AGAIN!!!