Regardless of your sexuality, as long as the fact is you are no longer romantically and sexually attracted to your husband and you feel unhappy and unsatisfied with your spousal relationship, you have to get out of it as soon as possible. Why? Because not only are you making yourself unhappy but that actually impacts your child as well in the end, even if you think the child doesn't notice, children are in fact impacted by the "vibes" coming from people around them, the general atmosphere and subtle cues. Secondly, you're also keeping your husband in a sort of limbo.

Now, having said that, of course your socio-economic situation is something to take into account, more so if you fear you might become a single parent(which btw you shouldn't, if your husband is a real father to the child, he should be a father regardless of your relationship, but that's a different matter). It's totally understandable that this has made things more difficult and is keeping you from ending things.

Maybe focus on trying to look for another job, for opportunities that can give you a bit of security, including some of the ideas in the reply above mine. You could try and confide in a friend or relative who you think is likely to be accepting and able to offer some help or advice.

I'll say this, I know many marriages of people even in my own family who stayed together for children or/and money or because of conservative views about marriage and staying in it no matter what. It's not worth it and it's not doing the child any good either.

My own example is telling. When I was 1 year and a half, my father fell for another woman and went to be with her. He and my mom never formally divorced purely cause it was, to them, more beneficial to just stay officially married. When his relationship ended and I was starting school, at the age of 7, they were both making good money and mom thought why not buy a bigger apartment together, for my sake, to have both parents under the same roof. They weren't a couple or anything, just formally married and living in the same house. It didn't help me. My dad was busy anyway and not hands on and he would have given me the same money and time either way. What it did do was keep both of them in a sort of limbo, especially my mom, although she had a couple of relationships during that time. Then they bought a house together to have even more space and make a good investment for my future. He died a year after but that's besides the point. When I was little I didn't fully understand what was going on, of course, but I grew up with a bad example of a relationship because there actually was none. You can raise a child together without being together. My mother's unhappiness rubbed off on me without her ever actually venting or doing anything like that, a lonely, unhappy person is different from one with a healthy relationship and happier life and that is important for the child as well.

Gay or not, your core issue is that this is not the right partner for you and this relationship is not doing you mentally and emotionally any good. I see you're from the UK, which means you're already in one of the more liberal, progressive thinking places in the world so that's one positive aspect. You could be bisexual, you could be lesbian, you could be bi but more into women, either of them is perfectly fine. Plus, you deserve to be happy, to find the right partner, to enjoy live as much as you can and have the relationships you wish to have.