cheating ? when your husband calls his exgirlfriend while at work using special days and times ?

He called her for five months with no intensetion of ever telling me . He even when to her house . She got mad because he did not want her to be friends with me . She has borrowed money in the pass and never has paid him back .She is always tell him that I am bad for him and holding back him things. But we have been married for 20 years and have 2 children . Before will were married she tried to break us . She went through numerous husband her self .