So I understand properly..1- She was spending tons of time on the phone with another person who could or could not be considered a romantic partner? 2-Or is that your reaction? 3-Your partner is suicidal and reached out to the friend because she felt she couldnt reach out to you?4- She is not the suicidal one but the friend is? is there any chance that your behavior in uncovering this stuff could be considered 'stalkish"? I ask that because that is never ok. Things can suck and it can kill you inside to know the details but when it comes to infidelity stalking IMO isnt ok. If she is the suicidal one I would put all your anger aside, put all your concerns about the friend aside and take her to a psychiatric ER if in crisis or IOP or OP place right away.