It can be very normal to lose interest, especially when you have little children. You could be more tired than usual, stressed, feeling the burden of being a grown up (if only we knew how much easier it was to be a kid!). It really doesn't sound like there is anything "wrong" with you.
Are you getting enough sleep? That can help TREMENDOUSLY. Are you getting some down time to relax and not stress?
As for natural things, try drinking red raspberry leaf tea. You can take it in tea form or in capsule form. That stuff works wonders for me in all girlie areas. I haven't used it in hopes of it making me more interested, but it helps to balance hormones, and it only makes sense to me that it would help you in that area. It also helps eliminate PMS (I get it bad some times, and it wipes it completely out!). It gets rid of cramps for me. It lightens my period and shortens it. And when we tried for baby #2, I couldn't get prego after six months. A friend told me about red raspberry (it was the first time I'd heard of it), and so I took it, and it balanced my hormones and I was prego two weeks later.
You want to take it three times a day, every day. Tea form is best, but it's pretty gross...at least I think so! So, there is the capsule option. It's more expensive, but I swear by this stuff. I've never used anything natural that had such obvious results.
Also, I'd suggest trying to alter your thinking a little bit and see if it helps. If your hubby is interested, you don't always have to be interested at the same level he is. Sometimes I'm just too tired to feel like taking the time to get interested (and I don't mean that to sound like I don't care...I just know that it would take a LOT of effort for me to get interested and it makes it more likely that I would just say no). But if I view it from the point of view that I love my hubby, and I don't need to pressure myself to be as interested (apparently I felt a lot of pressure from myself to try to make myself really interested), it makes it easier to be intimate more often when I didn't pressure myself like that. I don't know if that made sense. It turned into me wanting hubby to know I loved him and appreciated him, even if I wasn't interested myself, I was for him. It made it easier to be intimate more often. I've since found that my problem was lack of sleep! So, I try hard to make sure I get enough and it helps a lot.
I hope that helps some...
Good luck to you!