Solid relationship :) We've been living together for almost 2 years now, together for 5. I guess I feel like an asshole ditching our life together as soon as a cool opportunity presents itself, but he says if I want to go we'll make it work. That grant is an "unemployed person does a volunteering project" kind of grant. So no chance of getting it if I leave. It's not even really my project but I've been involved for almost a year now and getting that money would really help out. Same thing, feeling like an asshole letting down people that counted on me. Same with my friend's wedding - I promised I'll be there. I guess my whole problem is that accepting feels selfish and like i'd be letting down people and going back on my promisses? Don't want to be that person that jumps ship all the time.
Anyone who is mad that you missed their wedding to pursue a potentially life changing career opportunity is someone whose wedding you'd want to miss anyhow. There's nothing inherently selfish in pursuing goals, even in the case when it means that you have to sacrifice some previously planned activities that are meaningful to you. The virtue of sacrificing your own interests for the sake of relatively meaningless social engagements is non-existent. I would argue the virtue exists much more in sacrificing for the pursuit of that which is meaningful to you. A well-written and sincere card can allay any negativity between you and your friend.