OP I don't think it is an issue with you at all. I am exactly the same in the beginning I'm raging horny all the time, then I go off it completely.
It was only when I met my current man (who is now my fiance despite the fact I always thought I never wanted to be married) that things changed. Now I can go off it for months, then out of the blue I can be all over him constantly for a few days, a week, two weeks. Even the physical non sexual affection. And when I met my current partner, I realised that there is nothing 'wrong' with me per say, other than a traumatised past which has probably caused these intimacy issues in me. (Not you perhaps, I can't say as that's your business, but for me). But because he sees me, who I really am, despite the issues, and he knows how I love him because we communicate and I explain, and he gives me space and patience and a calm atmosphere and waits patiently out of respect for me. And now my sex drive does come back now and then (and he enjoys that while he can haha!) and the relationship is a long term one and a happy one. Because he allows the space and respect and understanding that leads to me eventually coming back to him in all ways physical. And that means everything to me. I'm not saying you have trauma by the way, just that this is how it is for me and because I found a man who sees the real me, respects me, gives me space, communicates and understands me, and we match in other ways that satisfy him until I come back to him physically, it works.
And my whole point in this is to say that I never thought i would ever be able to have a long term relationship because I always went off sex and even any non sexual affection. But once I found the right man for me, it works and my sex drive and affection whilst still odd (only due to my own past) is workable and not a problem.
So op I guess what I'm trying not very well to say, is that there is nothing wrong with you at all. I think you just haven't found the right partner for you yet. Please believe me when i say it. I always thought the same as you; that there's something wrong with me and I'll never have a long term relationship. But now I met the right guy, I found I can have a long term relationship, and there is nothing wrong with me (although I still struggle to believe that and often wonder why he puts up with me and what he even sees in me!).
You just need the right man. You deserve the right man. One with patience, understanding, empathy, the ability to see you; the person inside and love you for that, and find satisfaction from you in other ways that keeps him happy too, whilst your sex drive peaks and troughs. And you will. I believe in that because we all have a lot to give in non sexual ways.
Laughter, emotional support, shared hobbies and likes, a strong bond and loyalty, I could go on. But, whilst difficult to hear perhaps, this man isn't suited to you. And you and your little girl deserve far better. Please don't just settle. Please. You deserve better than this truly. 