Do whatever you need to do. Don't let his situation have an effect. It's not your fault he doesnt have a car etc. I think the best solution, however, is to have a real heart to heart talk with this bloke and let him know how you feel. Sounds like you guys have a good foundation, might just need a little work. I think the house might play a big part in your feelings. I bought a house (Age 25) for me and my Ex, then four months later she left me. The responsibility of a new home can really have a negative effect on a young relationship.
"Oh Lord it's hard to be humble, when you're perfect in every way. I can't wait to look in the mirror, cause I get better loking each day. To know me is to love me, I must be a hell of a man. Oh Lord it's hard to be humble, but I'm doing the best that I can." Mac Davis