Advice please????????

i am 5 months pregnant with a baby boy and my ex. bf who left me wants to know partake in the pregnancy and be at the birth. He even wants to talk about getting back together but i have a best friend pat who has stuck with me through everything and i have been getting really close and i dont now what to think? my baby comes first but who should i trust? i dont want to get my friend pat mad he is attending birth cles with me and parenting cles.