Hi scottles
Firstly I would like to say that I think its great that that you are doing all you can to keep a strong contact with your boys.
Going through a relationship breakup can be incredibly hard for everyone but when children are involved, it adds a lot of other complications.
I'm a non-resident dad too and rebuilding your life after you leave the family home can seem like a daunting task.
One thing you must do is get all the help and support you can and don't be afraid to rely on friends and family to help see you through the difficult times - its so important to keep yourself well and healthy.
The issues you mentioned to do with the houses and money are important to resolve but try to deal with them seperately from the contact you have with your children. If you are making contact with them and these issues get bought up, try to diffuse the situation by arranging an appropriate time when you can discuss these seperately from contact with your boys. Acknowledge that you want to talk about it but that it would be better to do with just your ex. Set a time and also a list of things that need to be discussed and stick to them.
If a conversation is going downhill and you find yourself heading towards an argument, step back and think of a different way to approach the problem or come back to it later. If you always strive to act in a calm and reasonable way, she will find it hard to retaliate negatively and this will help stop you reacting to things that might be said.
I couldn't agree more with actd - setting up a skype account is a great way to maintain face to face contact and is something i've just started doing with my son... Its great! There are lots of other ways to maintain contact too like email and letters. Making contact like this can remove the risk of an argument - although I realise at 4 this can be tricky.
Its really important that they know how much you care for them and you can do this just by reassuring them and asking about all the things that interest them and letting them be open about how they feel about all that is going on. Its important they feel confident about talking to you about difficult things without it making you obviously angry or upset.
You have to work very hard to get to the point where this is workable but it is well worth the effort. Please keep me up to date with how things are going. I'm sure your journey and experiences will help others who are going through similar problems.