What do you think of rushing into marriage and a relationship?

I just found out my ex got engaged today. I’m not in pain but I’m very shocked and confused. It kind of bruises my ego a bit and wonder why I wasn’t good enough for him and if he has forgotten me so easily. We were together for 6 years and he even had feelings for me when he broke up with me. He wanted to get back together but I could not go back to him because he wasn’t seriously working on patching things up.

We remained on good contact until he met his girlfriend. They’ve known eachother and have been together for 3 months. He is deploying next month and they got engaged. Do you think that he did it because he loves her and knows he wants to spend the rest of his life with her? It really makes me feel like our relationship was nothing at all to him to have been able to propose so fast. After 1 month of meeting her they were already saying they loved each other so much and completely.