I feel for you so very much, for many a decision can feel torturous when depression is a factor. I believe much in life comes down to management, as management is often what dictates the outcome of a situation.
Sounds like your parents or perhaps just your father may not have managed their/his separation as well as they/he could have, for your sake (if you are left with painful memories). This doesn't mean you can't manage your own separation in constructive ways which support your son. Perhaps some research could make a difference, if you do decide to separate. Such research could involve
- How to best help your son (mentally) through such a challenging transition in life. Helping him form a new and healthy sense of identity, in relation to what's going on in his life, is not an impossible task. As Ebsmeads mentions, kids are resilient (more so when they are receiving the best guidance and support)
- How to best support his mother through such a challenging transition. I'm not just talking about financial support, such as child support payments, I'm also talking about mentally supporting her in becoming independent from you. Of course, this angle best works when the split is an amicable one
Navigating an amicable split will require some skill development on the part of both parents as well as the child/children.
In regard to management, I'm left wondering about your depression. My own depression lasted about 15 years and I'll be the first to admit that I managed it poorly for a number of those years. Alcohol was my toxic 'go to' fix when I wasn't taking a med that worked or seeing an effective therapist. After having my 2nd child, my depression ended due to the supportive guidance and a life changing epiphany within post natal depression group therapy, of all things. Managing with the best support can impact not only our self but also the relationships we share with those around us, especially partners. Unless you and your partner are just not suited to each other, staying may involve you having to find new constructive ways of managing the depression. How we relate to our self definitely impacts how we relate to the folk around us.
I believe, at the end of the day, it is more constructive for us to ask not 'What am I going to do?' but 'What am I going to manage (and how)?' Having a plan is key and the most important part of any plan is flexibility; this way, we avoid becoming control freaks who end up being too hard on our self.