Advice please!

My advice is do exactly what you are doing , and be very careful about not letting your feelings show, their mum will always be their mum, no matter waht passes under the bridge.

It is very normal for children to want to be with the 'absent ' parent, and can get themselves very confused - this can be due to the fact that rules are relaxed when away from the main care giver . The family courts usually say that around 10 is the age when a child's opinion should be sought.

We had a very mixed up muddle - I had 2 children, he had 2, then we had one between us, his 2 stayed over every weekend, one weekend Saturdays only, as my ex had my boys that sunday, then the nest week we would have them over Saturday night and all day sunday.
My ex had 2 more kids, so my boys have 2 half brothers,plus a step brother and sister, and my husbands ex had another little girl.

We have seen all of the various playing each other off against each other permutations you could wish for - and luckily, with the exception of my husbands ex's parents( who wouldn't even speak to my 2 year old daughter at her 1/2 sister party! ) , all grandparents involved , of all of them, kept their counsel, included all the various 1/2 s and steps in with celebrations, and all have ended up pretty well adjusted adults, and friends with each other

Oh - and if they are his mums kids, they are his 1/2 brothers... my daughter only has '1/2s' but as far as she is concerned , they are just her brothers and sister !

There may be a book for children explaining these sort of issues - worth asking the library - i seem to remember one about a boy having 2 bedrooms

It sounds as if you are doing the right thing alreadyjacq making the time spent with him as lovely as you can. Four is too young to understand anything about his parents splitting up.It's sad.

Thanks folks for some very sound advice. The main worry comes from the fact that it is a very divided family but, as you say, we can just make our time with him as good as we can but the older boys understand what is going on and they now spend a lot more time with their Dad and the little one is wondering why. I think that, even though he is only 4, he has his worries and of course Mum has new boyfriend but we will be doing everything we can to make him feel secure.