My wife left me and she keeps on reappearing in my life when ever she wants.?

She was 17 and i was 18 when we met . One year later we moved in together. In our early twenty's we got married. Our marriage became turbulent for four years because I didn't have legal doents to be in the country. Five month ago she left the relationship after nine years together and she has been seeing someone else for four month. After both not talking for many month's she popped back in to my life saying she still loved me but at the same time she still seeing the other person. I do not have the to cut her off because i still love her with all my heart. I would like to hear peoples opinions and advise. thank you.