Is this person the right man for me? Should I stay in this relationship or should I go? Is he being faithful?

I have been dating this man for two years. He stays at my house Sunday thru Thursday and then the other days we stay at his apt. I was pregnant from him and lost the baby. I have two children already and he has none currently. He was married before for 11 years and he walked away from his wife because he said she cheated and didnt give him any children. We have discussed getting married, but first giving me an engagement ring before I have any children from him. He says that he wants to be a family but his actions say different. He always looks at other woman when we are out. I snoop on his cell phone and I see other woman calling and sending him text messages. He is 47 years old and i didnt expect this kind of behavior from him. Its really disappointing because I had so much hope for us. He comes home everynight but that still doesnt mean that he is 100% faithful. I have a hot meal ready for him evernight when he comes home from work. I take care of his overall well being. More than he does for me. Im taking care of two children and him but forgetting about myself. I dont feel appreciated at all I feel like I am being used. I dont feel safe and secure in this relationship. I am confused on what I should do. Please help me to try to figure this out.