When I separated from the mother from my child, he was 1 year and 10 months old. I was also thinking of staying together "for the sake of the kid", and she too, so nobody had courage to break up.

I had this on my head for a long time, and this single moment decided everything in my head:

I was absorved in my thoughts about how unhappy I was, and that I should stay on it because of the kid... While I was having those thoughts, my son was in front of me playing on his sand box and offering me in a very lovely way his toys, so that I could play with him together... He was offering it to me, but my mind was not there... I think I didnt even see that my kid existed, because I was so deep on those unhappy thoughts. At this exact moment, I got aware of my son, and I thought: 

*"Oh my god! He has been trying to play with me since a long time, and I cant play with him because I am always stuck on those thoughts. He will grow up thinking its completely normal to be unhappy in life, and in 30 years from now on, when he is stuck with a woman and completely unhappy, I will ask him:*

*-If you are so unhappy, why are you still with her?!?!*

*I knew that his answer would be:*

*-Because I learned it from YOU"*

At this moment, I got a shock and saw that this would be the most terrible thing to teach him in life: that unhappines is just OK. It is NOT OK to be unhappy, and I decided I would never teach him that. For me, happyness is the most important thing in life!

I also thought its better to happen now, than to wait some years.. It would be a waste of life, and it would be much harder for him, because he would already be fixed on the current family routine.

So I just separated from the mother, I live just 300 meters far away from my kid I see him a lot now: Every Wed, Thru, and every two weeks also Friday, Sat and Sun. I have ALL THE ENERGY OF THE WORLD for him now (before I had almost nothing). I have never loved my son so much before! Now I can enjoy him and be myself, without being bossed around by the mother.

If you need some book on the topic, I enjoyed the following:

 - The guide for separated parents, from Karen & Nick Woodall. This book has a very beautiful atmosphere, and if in the future you are feeling very bad about your decision, you can refer to this book to get strength.

 - Two homes, from Claire Masurel. This book will be for your kid: its a very beautiful book with drawing for kids, with a story of a kid who has a home with his father and mother, and showing the nice ways that their parents love him, wherever they are

 - The family book from Todd Parr. Its an illustration book like the above. You dont really need it, but its fun, talking about many ways a family can live.

If you just look the book from Claire on Amazon, you will probably find reccomendations about other books that you will like too.

Just some stuff that I didnt take into consideration at the time, and that maybe you should are:

 - End the relationshp in peace: Go to couples therapy, and certify that the feelings around you are healed and that they will not come back to **haunt you** in the future, because you will never be able to stop seeing your ex completely.
 - Be aware that after you brake up, maybe your spouse will find another guy who will spend time with your son too. Maybe you will get jealous/lack of trust about the guy, and maybe you cannot control too much what is going on... This will make you quite anxious.
 - Consider if the mother will be likely to move out of the city (and how far) after you break up... then it will make visitation a difficult topic, and this might cause you great psychological strain on you
 - Is your job flexible enough that will allow you to see your kid? Can you find a flexible job to help you?
 - Talk to people who experienced that first hand. Dont read too much. Talking to people feels more real and certain than reading books or asking on internet.

I hope I helped.