way to file a divorce

I am a married person for last 25 years. Immediately after 1-2 years of marraige I realised that we are too different for each other. My wife always has denied to stay with my parents. She always had troubles with my sisters and othe rrelatives. Due to my job, i havealways stayed away from my own state and used to visit our native once in a year. For those 15-20 days a year also, she used to complain and always used to be non-cooperative with my family members. Onn the other hand they always used to ask me to accomodate so as to avoid conflicts. We have very terrible atmosphere at home. My wife used to suspect every thing I used to do and used to blame me that I was tought by my mother or sister to do so. But since none of them never did so, I used to feel bad for them and it eventually added in increasing gaps between me and my wife. On every thing there used to be differences and as a result we hardly celebrated any birthdays for my two sons. We hardly had any celebrations on festivals. Even if I used to take them out during vacations, she used to pick arguments and at the end of the day everything was spoilt. I was pulling on like this until I met a lady from my workplace 7 yers back. we became good freinds and slowly started developing interest in each other. She also had troubled relationship with her husband and eventually she got divorced 4 years back. I find our relationship comfortable from begining. But just to ensure that it's not merely because of my spoilt relationship with my wife; I looked for another job in other city and moved with my family to new place. But I was in touch with my collegue over phones. I haverealised over these years that my collegue could be good companion for me and we have discussed about this as well. But I wanted my children to grow and before I get into this. Hence, I continued like this till today. Today both the boys are in college and grown up. Now I want to step into new relationship by divorcing my wife. But she is not agrrying for mutual concent. Can you pl. suggets me a way to come out of this relationship and marry my collegue?