1) This is difficult to address from my perspective because this lack of intimacy can often reflect some underlying issues. That being said, it is best to seek counsel from a family or marriage therapist who can work through this with both of you.
You are in my prayers
2) Istikhara is not meant for these things, it is for situations when a decision cannot be made due to complete uncertainty. In your case, you should try to seek counseling or professional help that will solve your marital problems