tough topic.

My boyfriend and I have been together 8 years. We do have an age difference. We had an unwanted pregnancy about three years ago. I was having a huge surgery so we chose to terminate. It was very difficult for me. My boyfriend flip flops on having a child. Sometimes he talks about it other times he doesn't want anymore. He has a 19 year old daughter. I've been around for basically most of her life. I am supposed to have my iud removed end of may and replaced. I do not want to have it replaced. I don't want a surprise pregnancy though. I would like it to be planned. I have a full time job with benefits. We have a four bedroom house. My car will be payed off the day after Christmas. My dog credit card will be played off so financially I will have the money. I know he flip flops about it and I don't want it to end up in an argument but I can't stay with someone who doesn't want the same thing. However I don't want it to be an ultimatum. How should I bring it up without sounding like it's one way or another.