That's odd. If I'm into someone, I'd like to spend more time than once a week. At least, twice a week. Life gets in the way but if you two have time talking on the phone in the evening, why can't she invite you over even just for a meal?
When you meet once a week, how long do you spend time together? How far do you live from each other?
When you get to a certain age, we all have our own pattern of doing things, routines and work, and get to appreciate having own time and doing some other things outside a relationship. But a relationship requires time to grow.... Perhaps it's not on her priority at the moment?!?!
“Really, sex and laughter do go very well together, and I wondered - and I still do - which is more important.” - Hermione Gingold-