Hello preciouslove,
Welcome to PC

!
Well, I can understand how you're feeling. My jealousy stems from major insecurity and self-hate. The result is still the same. I am very insecure ~ there's no other way to put it.
One thing that I've learned (over the years) is to swallow my strong impulse to voice my extreme fears to my bf. Some guys may seem understanding & give in, but that doesn't help us become stronger. Most other guys, on the other hand, become pretty frustrated with us for speaking up about our fears. My bf used to say, "I love you. When I don't love you anymore, you'll know it!" Not very reassuring.

I took that line as my hint to shut up about my intense fears, 'cause he sure as heck didn't want to hear about them.
Try to use logic with yourself, to get over your fears. Your hub is close to his Godsister. That's great! But, they most likely view one another like cousins...they're family. Chances of him going for her are really, really slim.
Regarding your hub's old friend from school ~ she's just that. Her time is really taken with her baby and bf. Chances of anything inappropriate ever happening between the two of them are also very close to nil. Remind yourself of these things whenever your mind starts wandering down Insecurity Lane.
I'd also advise you not to call your hub so much ~ try to knock it down to once or twice per day instead. Just to say, "I love you!" Make it short and sweet ~ don't Q him on where he is & what he's doing. The pattern you described yourself in isn't working for you or him... so you're going to have to change your pattern. I know that it's hard. But, fake it if you have to. It will become easier as time passes. Your hub will certainly appreciate the trust that you're showing, which will come back to you in a positive way. Just keep it up, it's worth it!
Very best wishes to you ~ take care!