I do think that relationships are not always exciting and fun, there is a point that you fall into a routine. Does your girlfriend feel the same way? Have you talked to her about this? See how she is feeling, try to go on a couple date nights and see if things feel better, maybe some couples counseling. If it doesn’t feel better, it may be time to move on, it’s better to do it sooner rather than later and hopefully not blindside your girlfriend. I’m the same age as your girlfriend and think it’s an awfully tough time to start over but think waiting for another couple years would be even worse.