My wife is pregnant with another man's child what are the legal and financial repricutions for me? she is asking me for a divorce, what do i do?

My wife is pregnant and romantecly envolved with another man he is married to another woman. She is asking me for a divorce, my only income is my army retirement income and my tricare healthcare coverage. She wants to be a single mom, but is hinting that she wants to keep all the benefits of a spouse of a army retiree, and she wants financial support from me. She is living with her mother and avoids my phone calls. What i am to do. Hire an at attorney or let her do it she is the one asking for a divorce since she now has another man in her life and his kid on the way. i feel violated and having to deal with the aftermath of infedility and abondement. I told her that she made started relationship but the divorce paperwork need to be completed and filed. she has no money and no job, she wants to still rely on me financially, and let her lover off the financial hook. I am really having a hard time with this debacle, plus the fact that i do not have the money to hire expensive lawyers.