Should I have a female friend on the side to occupy my time.?

Ive been divorced for about 9 mos. I've met a lady and we have fallen in love. My ex was a real b--ch and I was married to her for 18 years. The new lady and I talk everyday. But she also has an old guy friend she talks to whenever I'm not around. I'm a tad envious of this because he comes up sometimes in our conversations and I'm sure she mentions me to him. She speaks of him as if he one of the best guys in the world. I'm thinking the way I'm feeling like this is because I only have her in my life and I'm not the type to have various ladies. But I'm thinking I shouldn't put all of my eggs in one basket and have a lady friend who would be just strictly platonic in our relationship. Just someone to talk to besides my girl al the time and nothing more. Is this a good idea?