Wife's inability to trust causing marital issues

Trust is the basic pillar of a marriage. With that not in place, the foundation built upon that is shaky.
There are various reasons for why someone is unable to trust their partner:
previous experience of being cheated on/ having cheated
childhood experience of observing lack of trust in relationships or the reason for the same
personality trait of not being able to trust someone
influence of media/ peer groups
behaviour of the other that gives reasons for doubt
unacceptable to the fact that opposite sex can be friends

Try to figure out what your wife's reasons are and then when things are calm, try to talk to her about it. What you could try telling her is this "Honey, I know you're upset with me being friendly with other females. I want to know what about it makes you uncomfortable and perhaps I could do something to make you feel better about it. I'm here to hear you. At the same time I would also like to share with you my side of the view of this, hoping that you would understand me just as I am trying to understand you. My hope is that we are able to mutually come up with a decision that we agree upon in the best of both our interests." Hold her hand as you say to her "we'll figure it out together, don't worry". Once you're able to make her feel secure about your loyalty towards her, you would never have to worry about her being insecure.

Having a conversation such as this will create a space for mutual understanding and pave way for a safe space to resolve conflicts together in the marriage rather than just stating what you both want and resulting in frequent fights. Such fights result when both of you are talking but neither of you are actually listening to what the other intends to say.