Sex drive help

So I am 23 with 2 kids married for 4 years.

I seems like after having my kids my sex drive dropped lower and lower.

I love my husband more than anything, but our sex life isn't doing it for me. There has been ups and downs in our relationship also but I really want sex like I do. I think I have a low sex drive in my relationship out side of it. If that makes sense. We have tired different things in the bed room and I just can't find myself to come to husband or to allow him to come on to me because I don't want it. I was thinking about doing polyamory but I think that will ruin us. Anything I can do to get my sex drive back with my partner?