Relationship advice?

Long story short (yes its the short version) me and my S/o took a short break (2weeks).. Sort of we still acted as if we were in a relationship although when we decided we had reached personal goals we needed to work on we made it official again. Well i fell pregnant with our 2nd and before i got a positive test he came clean and told me he got another girl pregnant... And she was 5 MONTHS... Im trying to work with him (he was lost mentally and confused on our standing is what he said when i asked him why) but im lost on how to handle it because texhnically we had split for the few days when he visited her in WV around christmas... (We live in FL) But he was still treating me as if we were together... He said he was scared to tell me and she is also his friend for 9 years now who has been in love with him since day 1. She automatically doesnt like me and he doesnt want to involve me when i just wish every one would cooperate... To be fair her son is my sons half brother and i WILL be around her when it involves my child... Im just so confused and so torn like i need advice ladies... Do i contact her and try to resolve her issues with me? Leave her alone? (He doesnt want me to speak to her at all) I still love him with all of me and it truly sucks...