Trying to let go

Hi there, a friend suggested this site for me as I seem to have got myself into a bit of a mess since splitting up with the father of my kids and don't seem to be able to move forward.  I was with him for 10 1/2 years full time (lived together as a proper couple etc) and had two children together who are now 10 and 6.  Yes we had our ups and downs (as most couples do) but as a whole we were happy together and both had a understanding that our kids come first and it was all about our family life.  Then 2 years ago his mom passed away after a few weeks of being very very poorly.  I didn't particular like his mom due to certain things, which my partner always said that he agreed with me on and that he understood why I felt like I did.  However he then turned on me when he was told his mom was dying and said that it was over between us and that he would be moving out as soon as possible but could I just allow him to stay until it was all over with.  Then he got in touch with his ex (swears it wasn't anything other than she always liked his mom), however at the time he denied it to me when I confronted him about it (but I knew what was going on but was made out to be paranoid, which in turn started messing with my head) the rows that was going on were horrendous, the atmosphere awful so in the end after his mom had passed away I asked him if he was certain it was over and he was leaving soon anyway to please leave now (as he was out all day clearing his moms house out anyway) and thought some space between us may help.  He chose to go back to his moms house to sleep there as well (something of which he throws and me that I 'chucked him out' after his mom died) because his moms house was council I knew he only had 4 weeks until he had to give the keys back, I visited him a couple of times and pleaded with him to come back home and not to get somewhere and that not to make a decission like this whilst he was suffering with grief.  However he was ademant it was over and he was getting his own place, which he did a few weeks later.  That was just under 2 years ago, since then we have been 'trying' to make it work so that he can come back home.  However he comes to stay over of a Saturday (he just turns up when he's woke up usually after mid-day) and goes back to his of a Sunday night, occassionally (when i've moaned about how can we make it work when we don't see each other) he will stop sometimes one (or we have even done 2 nights) during the week.  He does work a late shift 2-10.30pm are his normal hours but I know that he has been finishing sometimes a few hours early over these last couple of years as he is on a once he's finished he can leave type job as sometimes he is there longer than his hours however he never just popped to see us, instead went to friends houses or out with friends.  He gradually started spending more time with old friends and I found myself keep banging my head against a brick wall that please just spend more time with us, it's going on too long for the children I want you to be back here sooner rather than later.  Which he always then agreed with and 'promised to spend more time with us'.  We have taken holidays together and at Christmas or birthdays he's always come to mine and stayed with us for those periods as well.  However despite my constant pleas of please give us more time he never seemed to, cue me losing my temper and then he'd say look it's you putting us two steps back! Sometimes, i've had enough and say I can't take anymore of this it's over for good which then he's come to me and said that he thinks i'm making a big mistake and he does want his family to work etc, or sometimes after i've lost my temper he'll run away shut his door and say that forget it, it's never going to work and then I find I go apologising to him and asking him to keep 'trying'.  Over the last few months (after he told me that he would come and rent somewhere new with me in a couple of months) we had another blazing row due to me feeling like he has his 'single man' life then turns up for his 'family life' at the weekend.  Bearing in mind during all this time the kids have been with me constantly and I haven't been doing anything or going out. It has now got really bad, we are no longer on speaking terms, when we do speak it ends in rows.  A couple of weeks ago it was agreed he has the kids every other weekend he should of had the kids from 11am but turned up half an hour late and obviously very worse for wear from the night before, but acts like 'what's your problem, sorry didn't intend getting drunk last night, just went round a friends house and got carried away, and look i'm sorry i'm late I over slept, no big deal' when I flip my lid.  I broke down and cried to him told him I was worried that he doesn't seem to be the dad he was when he was at home and feared his friends are no good.  I spoke to him for a couple of hours and we both had tears, and again I found myself saying to him, please sort your head out and just spend time with us, we can make this work if you put the effort in.  So he had the children that night and the nxt day phoned up and asked if I wanted him to come back with the kids and stay.  I asked if he was sure as perhaps he just needed a bit of time to make sure (as things had been said during the couple of hours talk the day before) so we decided to go for a meal and then all week we we're speaking on the phone.  Come the Friday before 'my' weekend he had txt something to make out he couldn't speak to the kids for a reason but I happened to find out he was out, so I 'pulled him up' about this and cue us not speaking again.  I have been down now and said right if this is it we need to discuss exactly what is going on with the kids, when your having them, what happens for holidays, birthday's etc and he is refusing to speak to me about it.  I have said to go to family medation to come to a agreement but he said he won't attend and if I go to solicitors he will ignore the letters.  He seems to think that we can discuss all this at a later date and that for now we'll just 'plod' along as we are (he having the kids every 2 weekends and phoning the kids each night to say goodnight) nothing more has been discussed (in terms of if he finishes early what will happen, school runs, holidays etc) and I feel that for me to move on I don't want to have everything in 'limbo' until the situation arises and then we'll talk then.  My problem is as well that because i've put so much time and effort into this over the last two years and haven't moved on (where quite clearly it seems he has or is) I don't now seem to be able to think of anything else, i'm over anaylising everything, where the hell did we go wrong, should I have done this, if only I hadn't done that.  I'm also constantly fretting of how i'll feel if he meets somebody else as know that it will hit me hard and I feel like i've got this huge weight on top of me, where I don't see it getting any better.  Thank you for taking the time out to read this and any thoughts or advice would be very much appreciated x