This is nothing you will not do, the mother brought him to the light, brought up, made him the world's best porridge and consequently in his life she will always be in the first place. Mother in his life will play a unique role. If you find a common language with her, get in her face a powerful ally.
The former woman
Regardless of how long they were together, broke up, friendly or not, every woman with whom he spent some time in his life will always be present. Your partner will compare you with her, you will stand of their holiday spent together, sex and daily rituals. Of course, all this situation will worsen if one of them did not agree that their relationship is over.
They grew up together, went to karate, they have friends in common and they meet regularly in the pub. They laugh at jokes that you don't know, discuss and people you don't know. This is his best friend, and nothing you can say against it, because they can not determine who he can be friends with and who – no. Perhaps it is, indeed, innocent relationship in which there is nothing more pure friendship, but God forbid, if you do not like it!
Maybe she doesn't look like a sex goddess, but, unlike you, is essentially unlimited time for chatting, since, carries with it, at least eight hours a day. They face the same problems, complain about one boss, gossiping about coworkers, what we can conclude is that they are very similar and understand each other. Not by chance in fact, most infidelity occurs between coworkers.