Well he sounds a spineless wayne kerr to me and obviously doesn't know what he is missing out on, as far as fatherhood and being a life partner is concerned. Flirting is permissible, crossing the line is...well, crossing the line. Fantasies are often best left well alone, he'll find that out soon enough. Hopefully through a bout of raging nob rot and genital warts.
Cherish your new life. Cherish your beautiful baby. Cherish the new chapter that awaits and know that YOU are in control of your own destiny.
I hope you find what you're looking for in love, if that is indeed what you're after? Rebound sex is great for us animalistic males, but can be soul destroying for a single mother, look after your own best interests and f**k anyone who messes with your bubble.
