Is there a way we can email offline? I'll look into my profile so maybe you can email me from there. I am new to this site. Your post just hit so close to home! Funny (well not actually) but I am in almost the exact same situation as you. I am a single mom too (of a 5 year old) and dating a guy for 8 months. His ex is due to have a baby next week. I would love to talk to someone in the same situation. Its hard talking with friends since this is such a hard topic.
Hope to hear from you.