I think if a man, knowing his wife and daughter have tickets booked home and says I look at a man and thing Phwoar, he is understating things dramatically.
I think you need to have an honest conversation with him, tell him that his treatment of you is callous, cruel and nasty sometimes, and that now he is saying he might be gay, he has to understand that this is an issue that will potentially end your marriage.
As you are from the UK and abroad, that you would have to come home, and he needs to think through how life will be.
I also think YOU need to do the same. Think through the pros and cons of sticking in a relationship where ultimately YOU are not wanted. It's genuinely not fair on you to stay, it's not fair on your DC either.
You need to have a complete drains up, get everything off your chest and out in the open. Won't change anything ultimately, but it'll help you offload some of the hurt, frustration and emotion that you have been bottling up. You need to express it, he needs to hear it.
Being single is better than being in a dead relationship, and if he really IS gay, that is what it's going to be. You can't stay in a relationship like that.
I'm so sorry, I had a boyfriend do this to me, and it was excruciating, I can't imagine the pain you are feeling now that you have DD etc. It will get easier to cope with.
FWIW, I did meet some men that were married, did have kids, but ultimately couldn't live as a heterosexual man. The conflict was immense, the fall out really painful. Yes they are being selfish, but tbh, when it comes to dead-end relationships such as this/abusive, the facts of the matter are not going to change, it's not going to get better, is it? If a woman was in a relationship and knew that it was never, ever going to make her happy, was sexless and eventually resentful, everyone would tell her to leave. it's not fair on the other partner.
This situation is not fair on you, and tbh, not fair on him either.