Is it normal that i like my husband to have sex with other women?

I'm not talking about a threesome, but about him going out with other women while I'm not there and later having sex with them. It has always turned me on. I have even went to pick him up one time from a woman's house where he had stayed the night with her. He told me while they were waiting for me they had just finished having sex again. That really turned me on and I ripped open his pants to take out his penis and immediatly started sucking on it. I could smell and taste both of their juices and that got me off even more. But this is just one time I've done that. Usually I wait for him to come home. Hr usually just goes out and has sex then later that night/early morning he comes home. He tells me all about it, what she looked like, what they did. Just everything. And of course it turns me on and we then have sex. We don't do this all the time. And i don't think of it as cheat since I know about it and I like him doing it and even encourage him to do it at times. We have children and I'm in college. We have a great sex life just we ourselves. Its not like I can't or don't give it to him. Its just added a little extra spice in there. We've had threesomes and have enjoyed them, but for some reason I like this better. And also if I wanted he's told me many times before I can do the same with guys or girls, whichever turned me on. But right now I'm not that interested and I get off on him going out and doing it. Its only an every now and then thing, not every weekend or even every other wkend. But I was wondering if others did the same or if they think about it and want to do it. Thanks! :-)