me and ex had trial separation (four months). She used that time to have two affairs and a couple of one night stands.
She used the "trial separation" to postpone the actual telling me that the marriage was over.
Trial separations can work if both people want it to work but my experience and those of friends suggests that one person uses that time to date other people, go out and act single forgetting the reason for that trial separation.
Split the time you and H spend into the following
With friends
Work
Together With children
One of you with children
"existing" along side each other
"quality time" With each other
Do you agree that you have the balance right. What tends to happen is that over time resentment/little issues causes you to spend more time with friends / other interests and less "quality time" with each other.
I for one think if both people want the relationship to work is to work together (through councelling), communication with each other.
Do you still have the same hopes and aspirations. What do you like about your life. What gets you down. What would you like DH to bring a smile to your face/make you happy. What would he like you do.
Timeline your relationship. When did feelings from ex start diminishing. Was there something else happening (kid being born, work not going well, death of someone close, money issues).
I hope it works out but i have seen a number of people have trial separations and in each case one person was not committed.
If you do go for trial separation. Do try and put boundaries into it:
ie
how will financials work
How will contact with DS occur
How much can you and DH contact each other (ie nothing for two week unless to talk about son, then two phone calls, one meeting a week
Can you date other people
Can you still have sex (there are people who have trial separation but meet up for sex with each other)
Who do you tell. ie you may agree that you can each tell one or two close friends all the issues but everyone else is told "we are having a trial separation to work things through but please try and avoid taking sides as we are working to get back together"
Can you seek legal advice
Time for separation. ie agree that it will be for x months.
Are there certain topics NOT to suggest in first month/ two months
What do you tell DS
Will you still have family time with DS. ie not sure how old DS is but if he's little (which i get the impression he's not) you may still meet up for an hour or two at weekend to go to park etc.
As various people have stated what do you want to change. What does ex want to change. Are the two lists compatible with a little compromise or are there some serious deal breakers.
Good luck