Well, my husband and I have discussed this since he was having a hard time with his envy/jealousy. I have a boyfriend, more of a fwb, that I see lots here at our house with hub, but I have been to his place one time. I'm not sure it was quite an "overnight" since I didn't get there until 11:30pm and was home by 5:00am. Hub had an awful time with it. The entire time I was driving over there (he's in Spok like you) hub was sending me texts, freaking the hell out and what not. I just ignored it since I knew he was having his own personal issue. He had given us the okay to be alone and then all of a sudden, lost his friggin mind (that was in July).
Now I'm about to meet a new guy and hub asked if I was going to stay overnight. I said after that incident we made an agreement no overnights right away with any one new but that eventually they would be ok. Part of what makes it hard for hub is our 2 year old. She wakes, not every night, to nurse. It's actually easy for him to just make a bottle, but that was his reasoning and I'm letting him use it. We also have two other kids, 15 yo girl and an almost 8 yo boy, so it's just best for them I'm home before they wake.
As I'm pretty new to this, I can't say what you can do to get over your jealousy except you'll need to figure out why you are jealous or insecure about her staying there. Is it every weekend? How many nights will you have her staying with you? Are you involved with any one else? Do you have a hobby you can do? There are a lot of stories about this and other posts here. I'm sure the more you read, learn and get opinions, you'll come to terms with your feelings.
Good luck on figuring this out. I personally know my husband loves me so much that I don't experience jealousy. Tomorrow he's going to meet a new girl. I'm not sure what they'll do but I'm sure they are going to get intimate. I'm 100% okay with it and smile every time I think about it.