My daughter's father can't be trusted

I am 28 years old and I have been in a relationship with a man for over five years and we have a three-year-old daughter.  

He works abroad and after every three months he returns home to check on his family. He usually stays around for one month. 

However, when our daughter was two years old, he changed. He stopped calling me and whenever I asked to meet him, he would give excuses or hang up the phone.  

Recently, he took our daughter to live with his elder sister. When I went to check on my daughter, I found another little girl. I later discovered she was my daughter’s half-sister and was only a week older than my daughter. 

The two girls look like twins. My boyfriend never told me about his other daughter and none of his relatives told me about her. 

He is now in another relationship with another woman who does not know his history. I really loved him, but when I discovered the existence of another child, who was the same age as my daughter, I lost the trust I had in him. 

I need guidance on the way forward, although I have already decided to end the relationship. 

Belinda