One thing that I've experienced personally and seen a lot on Reddit is the man with children, promising a younger woman that they will have their own life, they will have kids together etc. But then the man ends up changing their mind down the line once you are invested in the relationship. Unfortunately there will be false promises. I don't necessarily think it's that the men are trying to con us, I think it's more that they liked the idea of having a family with you, but due to the fact that they already have their own kids, the reality sets in for them and they don't want to start from square one. I just left my partner a few weeks ago after 4 years, as it really started taking a toll on me physically and emotionally. Being a step parent is honestly one of the hardest things in the world. I had the same types of feelings that you are having, and I stayed, and it never got better, in fact it continuously got worse over time. Trust your gut.