ladies I need some advice...

So I've decided I want to start trying for a baby. Me and my partner have spoken about having children together and it's something we both want (he has 2 children from a previous relationship). I want to suggest to him that I'd like to start trying for a family of our own but I'm so worried with how he's going to respond. I'm scared that he's only told me he's wants children with me to keep me around as he already has children. Please can you help me with how you think is best to handle this situation or from experience you've had yourself. I just need to know if I'm wasting my time with this man or not as we've been together 3 years now.