First off you need to evaluate all medical reasons why she acts like this such as PPD. Depression would explain a lot.

After this is ruled out you can try couples counseling and sex counseling.

Because of you mentioning her being on her phone alot I also have to mention cheating as a possibility. If she shuts down the two first suggestions cheating starts becoming a more likely option. I would start snooping if it reaches this point.

Make sure that she understands that your relationship is on the line if she doesn't agree to the first two suggestions.