Engagement jealousy

My boyfriend and I got together before any of his or my own friends got together( over 2 years ago). They all started getting engaged last year, and although I am so happy for them I can't help but feel jealous! Some of his friends fiancée's have been hinting at the fact that maybe he doesn't want to marry me since we aren't engaged, but he swears he does and he just wants to get me my dream ring but can't afford to right now. It makes me feel a little upset that they are all ready to be married in summer 2018, and I'm not even engaged. I know that I want to spend the rest of my life with him, and I really think he wants the same. But I just can't help but feel a little bit upset. We are planning to become pregnant and I know a baby is a bigger commitment than a marriage but I hate myself for feeling this way. Has anyone else felt this way? How did you cope with it?