The timing of the miscarriages---before your first child, and the very last one being a tubal pregnancy, would cause me to reject the hypotheses I offered earlier. Something in going on 'inside of head' that she isn't being clear and transparent about with you. It may be that she doesn't fully know herself why she isn't feeling love for you anymore. You describe a marital situation that is going 'downhill'---that isn't likely to get better on its own I would at this point, recommend marital therapy.
I think you could get her to agree to marital therapy if you took the proper approach to it e.g., "I am very concerned about state of our marriage and I'd like to either find a way to improve it and move forward, or bring a speedy end to it so you can perhaps find new happiness as a single mom. I deserve to be with someone who loves me; and I don't want to stand in the way of you being happy if you feel you don't love me. So I want to suggest that we go to marital therapy to simply figure out what is going on and make some clear decisions about what to do about this relationship---can we improve it, or do we need to go our separate ways?" This is the quickest way to get to the truth of the matter
and discover if there is hope for your marriage, what can be done to improve it, etc. If she simply doesn't want to be married to you, it is far better to find this out now, so you can move on, rather than drag yourself through a great deal of emotional distress, ambiguity, anxiety
about 'not knowing' etc., for several years, only to discovered that you've wasted this time 'waiting' for things to get better----when they never will.
What do you think?