Weird totally ok with having child but takes forever to pop question.

So my bf has known I want to get married for at least 4 years now. He's been waiting for the 'perfect time' to do so and I know he plans to ask this year but don't know when. We r open about it. So anyway we had unprotected sex and I said what if I get pregnant because I want a baby with you it would be awesome. He said that's fine you know I would be all in and we could do a good job. So I'm thinking to myself why is he taking so long to marry me when he knows that's what I really wanted this whole time and he is totally OK with having a child no problem. Honestly he would be a good dad and our relationship is awesome. But ya know it's in the back of my mind like... Suspicion! I mean this all with a light heart but herm.