should I try or not ??

ladies I have a dilemma!! I've been with my guy for ove two years now... and to me I've hit my breaking point!! My bf is in the military and we've been talking about having a child for a while now!! We've been trying the last couple of months but when he hears that I'm ovulating we don't have sex... (shameful)... I've recently found a letter he wrote to some woman named alexis!!! me and her conversed and she told me she's gay (she's not). she even told me they were friends and will continue to be friends after she called his phone and I picked up!! the problem I have with this situation... today he moved to a different squadron and it's in her squadron!!! what should I do ?? I talked it over with my sister's and of course I should leave and don't look back!!! But my heart is still attached I'm lost!!! I need some advice!!!