The ultimatum is bogus. Still, there are a few pertinent questions that have not been answered:
How much time per day do you spend with your girlfriend, on average?
You say your training has picked up significantly over the last six months, which has probably cut into your time with your girlfriend. Have you made an effort to make it up to her or carve out time to be with her?
Are you pulling your weight around the house now that your training has picked up?
Do you express a sincere interest in her passions, or do you just constantly talk about your running?
Select the response that most accurately depicts how you'd respond to the following hypothetical situation. It is Friday night and your girlfriend asks if you want to go out for dinner. You:
a.) Say no thanks, you were planning on eating the leftover chicken, rice and broccoli dish you made for yourself last night, plus you have to foam roll and do a core workout.
b.) Suggest a place that both of you like and take her there.
c.) Decline to go out, but offer to make something, whatever she'd like.
d.) Decline to go out, but offer to make and share a dish that has been approved by your nutritionist.