Married since we were 19 with 3 kids is it over?

So my wife and I have been together since we were 16 got married at 19 and are now 25. We have 3 kids together. I know were young to have children especially 3 and I know we were young to get married.
Recently though our sex life has been trash to the tune of maybe twice a month. She just doesn't seem interested. I know sex isn't the only thing that matters in our relationship but it is definitely hurting at least my self esteem. Should we get a divorce? Like I said we have 3 kids my biggest fear is never finding someone again because I feel most women my age wouldn't want to date someone with 3 kids. I'm not co dependent in the least but the thought of never having a SO again seems scary to me. Divorce seems scary to me. I don't know just throwing it out there. Is she cheating? Do I move on so I can be happy and feel loved again? Any help is much appreciated.
Married since we were 19 with 3 kids is it over?
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