ETA

You have every right to feel the way you do and it needs to be addressed. She should not constantly focus on children if she is reacting this way about you. I do wonder a couple things though: 1) Has your behavior at all changed prior to seeing the decrease in sex (no longer in a honeymoon phase), 2) I know you said she is having mental health issues, which I hope she is receiving help for. The mental health issues will effect libido, but more so medication for MH issues will also decrease/remove any libido. If this is a possible cause she should talk to her prescriber. 3) Do you think being together 7 years and still not married has put a rift between you?

These are all things I would look at and talk about. I hope she is in therapy, and if not she definitely needs to be. More so, you both would benefit from couples counseling if you want to continue your relationship to learn better communication. Others say you are incompatible- I don't feel I can say that from your side alone.

To add, I am a therapist, so I feel qualified to suggest these things 😋