FH wants me to be a stay-at-home. Neither of us have been sent to
daycare or anything when we were younger and he plans on having a baby
I don't like the sound of this. You're saying that your FH wants you to be a stay-at-home-mom and that HE plans to have a baby soon...what do YOU want? Maybe it's just the way you worded it, but it sounds like he's calling the shots.
If I remember correctly, you're a college student. I urge you to complete your degree regardless of whether your FH wants you to work or not, and regardless of whether he wants kids immediately. That way, you'll at least have your degree to fall back on if something happened or if you needed extra money. Sure, nobody thinks that their marriage will fail or that their FH might die young, but these things happen and you need to be able to support yourself and your future children if they do.
Also, I'm sorry to be a jerk, but I feel like nobody is pointing out the obvious. How can you go from 'I have feelings for this other guy and I'm thinking about leaving FH for him,' to 'Not only was I wrong about my feelings, but now FH and I are ready to have a baby right away' in the span of one month? I think you need to speak up and be honest about your feelings. He might want kids right away, but it doesn't sound like you're ready.