Thank you for your question.
Let me qualify my answer by saying that none of us are priests or councilors. We mostly answer theological questions about what the Church teaches. At least that's our expertise.
That said, this kind of situation really needs a priest and a face to face session, or two, to sort out some of the details that a priest would know to ask.
However, before returning to the Church, I was a Protestant Minister and have had some experience in pastoral counseling. I'm not a certified counselor, nor am I active in that kind of ministry anymore but I will do the best I can to give some biblical advice.
First of all, the feelings you're experiencing are natural given the situation but that doesn't mean they are healthy, and that you want to hold on to them. Resentments are a form of unforgiveness and, just as important, they hurt you. They lead to bitterness, and that can actually lead to a variety of both psychological and even physical problems. In addition, it will affect all your other relationships.
So whether you decide to stay with him or not, you need to pray that God heals your heart and changes his. Just as important, you need to pray for him. That's the biggest act of charity you can do for him, even more than helping him in his illness.
When you marry someone, it's for better or worse. If a marriage is valid, its covenant and covenants can't be broken. If the vow of marriage is broken, then the people get broken and that is exactly what has happened to you.
Assuming the marriage is valid (and we'll deal with that shortly), you should do all that you can to salvage it. That's assuming you're not in any kind of physical or psychological danger.
You mentioned your husband had an ex—; I assume an ex-wife. If that is the case and the first marriage wasn't annulled, then there are other issues that come up with respect to the validity of the present marriage. I don't want to get into all that. It's something you need to discuss with a good priest.
So let's get back the specific issue you asked about.
Christian love is more than a feeling or an emotion. It's a choice followed by action. Sometimes it means acting as though you love the person, in spite of the fact that you don't feel the love. In doing so, as you pray for God to heal your broken heart and you pray for him, God may rekindle the emotional aspect of your love. But either way, love involves commitment and action, not just emotion. Emotions come and go all the time. It's not uncommon for people who are married for long periods to fall in out of love more than once throughout the marriage. That's even without infidelities involved.
However, if you can't do that, then staying with him may cause yourself, and thus others, more harm than good but you need to really give this fair shot. At least that's my advice, based on what little I know of the situation.
Therefore, I cannot overemphasize that you need to see a good priest. Set up an appointment. If you've been away from the sacraments, when you meet with the priest, that's the first thing you need to do: (receive the sacraments). You need to explain the whole situation, including the circumstances of your marriage . . . as it relates to a previous marriage or marriages.
He will be able to walk you through everything and advise you far better than we can via e-mail.