Can people who are married have friends that are of the opisite without involveing there married other?

My wife believes in having male friends. I have talked to her about this and told her how I feel but she does not seem to care. After having an internet male friend fly in and stay at the hotel down the road from us. He was here a week, even in our house. She never told me and I found out while he was still here but she let me do all the work in finding the truth until he was gone. We moved past this it was a little over a year ago. Then 2 months ago she reconnected with a male highschool friend and they talked about meeting for fun, what ever was meant by that Im not sure and he even had the guts to call and ask for her while I was there. We faught about that, done and past it. And now my wife left her cell phone at home. Shes been really clingy to that I have been trying to give her the benifit of the daubt, but its hard. She called and said she left it at home I looked couldnt find it. lator her sister called from it and I found it. Yes curiousity got the beter of me. I checked it out. All history was not bad. I noticed my wife had the guys number that stayed for the weekend at the hotel still in her cell phone and another non local number. She only had letters for the 2 peoples names. I have no idea who the second person is. She called him in the memory yesterday at work. What should I do We have faught about this for over a year now. We are married with kids and divorce is not an option. What exscuse is exceptable. How can I just stop caring. All she says is they are just friends and its normal for married people to do this. I have no felmale friends, except the ones she has. I go out of the way to respect my wife and not She has no idea how I feel, I tell her and she just laghed at first, but lator told she had no idea why I felt this way. What should I do?