How to say I want another one???

Back history, I have two girls 21 and 17. spent almost my whole life raising them as a single mom. didn't date didn't see people just raised my kiddos. I then found my SO a little over a year ago. He has four girls all not at home. my youngest is the only one at home. he also has four grandbabies with his girls. He's 47 I'm 41. I would love my second chance to raise a baby with a loving dad and a mom. I am in a place where baby could n with us while I worked and made money. we have room. Life is good. I can't stop thinking how another one would be so great. we haven't used protection at all so he knows there is a possibility for me to get pregnant. however I would like to really try to have one. how do I bring this up. He's an awesome dad to his kids and mine even though they are older. should I just openly say something like I want to try. how do I go about this? thank you for advice. baby dust to everyone.