All day Sunday to Monday morning every week doesn''t allow either of you to have a weekend away, with or without the children. Also you both have to get up every Sunday morning, which might not suit either of you either.
But why so few visits as the alternative? A much more common arrangement is Friday school/tea to Monday morning school on alternate weekends, often with a midweek night school pickup to school drop-off as well.
Honestly? It sounds like you don''t want the children. Whatever the reason, who ever you want to blame, is unimportant. From the picture you paint of your stbx,, it sounds like she doesn''t want the children either. I hope to god your kids don''t pick up on this
Reading this thread, I have realised that there are worse things for a child to go through than a residence battle where both parents want the children. That is, to go through a battle where neither parent wants them.
What you need to remember when trying to make any arrangements regarding children is that contact is for their benefit, not the parents (although, obviously, parents benefit too).
I can''t find from reading your previous posts how old your children are, which could make a difference to the proposed arrangements you wish to make. Teenagers, for example, may prefer a more flexible arrangement.
A weekend once a month seems to me to be a very low level amount of time to be aiming for with your children. I know you have spoken of your frustration at parenting on your own due to lack of family and a support network around you, but that shouldn''t be a barrier to spending as much time as possible with your children. There are plenty of single parents who use this forum who can give you coping tips and ideas.