I Look Back And Laugh - I Look Forward And Throw Up A Little

So many entries regarding my boyfriend and his bipolar disappearing acts.  So many "poor me entries" as I dealt with my own depression and anxiety attacks.  So many holidays dreaded because I wouldn't see him.  Even my sister confirmed bipolar people disappear from time to time.  It hurt me but I got it.
And now I find that within a couple weeks of the debacle at the airport here, he was dating someone else and lying to me about it.  He told me his brother was going to Scotland on business and I encouraged him to go to Scotland to get away from his crazy family.  He went.  Several times.  To see his Scottish girlfriend.
I didn't know, so bought a plane ticket to go see him, as we discussed.  He canceled on me.  He had a date with her that week!!!!!!!!!  He said that was planned in advance.  WTF?!?!?!?!??!?!?!??!?!??!?!??!  I ate the cost of the ticket as well as most of the cost to bring him here in the summer.
He told me his family was using his room at their house for out of town relatives and he'd be spending time with his brother to make room over New Years.  He didn't even call me.  But...he had his girlfriend in his house.  No out of town relatives.  
I sent him gifts.  I got a Christmas card and a birthday card.
Over Valentine's Day his brother had a business trip in Scotland...his brother didn't go.  But Leif did.  To spend Valentine's Day with his girlfriend.
I got a card.
I found out while he was on a weekend away (at his brother's so he said,) actually with yet another woman in another city.  I confronted him.  He called me crazy. He literally called me crazy.
I explained the proof I had, and all of the sudden he was sooooo sorry.  He couldn't stand not having a physical relationship.  He didn't want to lose me.  He has pressure from his family.  He did need time away from them.  And apparently telephones, computers, etc.  But not from other women and their telephones.
He has promised once again to be true.  Wants a winter holiday with me.  Of course I'm paying my own way there because he's never paid me anything from last year's travel fiascos...but he's renting the cottage.
And God Dammit!  I want to forgive him.  My absolute pain and feelings of inferiority come and go in waves.  I'm an absolute doormat.
I know it's not normal for a 32 year old guy to be celibate.  It's been 2 years since we've been together.  Not because I haven't been willing to see him.  Because he's not making enough money for a hotel for us, and his family don't like me enough to let me stay with them.  But apparently, he has money for travel to Scotland, cell phones, dvds, etc.
I know I'm disgustingly sniveling and a complete idiot.  How do I stop loving him?  He's articulate, artistic, attractive, and we've had this incredible connection since we met 3 years ago.
I have to start standing up for myself.  I won my Social Security Disability case.  YAY!  I planned the holiday in England without him - visiting relatives and am going regardless, to see them and have some time away from my rather dysfunctional close family.
But how do I stand up in other ways?  I want to say, "Hey Asshole!  Where's MY Christmas present?  Where's MY Valentine's Day flowers, and where's all the money you owe me for the trip where you blew me off for that Scottish bitch?!?"
I'm so angry and I love him so much and I'm up and down.  I'm on 3 antidepressants, a mood stabilizer, clonazepam, lorazepam, and now a blood pressure medication.  
I just need something to hope for.  I just want so much for someone to want me.  I was a caregiver for 20 years for my mom - I want someone to take care of me!  Now my sister is getting ill, and I see it happening all over again.
And I want to believe him.  I know he loves me.  But he's a coward.
I know anyone reading this will tell me forget him - never look back.    I just wish someone would tell me how.
Feel free to wipe your feet on the doormat.