Can I be upset - engagement

Been with my bf for 8 years. Owned a house for two and been ttc for 3. I would have thought that we would be engaged by now, I was anticipating it at our 6 year anniversary. Anyways, any time I see someone I know get engaged I can help but tear up. I don’t do it on purpose to make my bf feel bad or anything, it’s just like a natural reaction at this point. I want for it to be me so bad. We talk and have always talked about getting married, it’s on the table he knows it’s something I really want. I just don’t understand why he’s waiting so long? Is it okay for me to be upset about it?