It's been 10 months since I am with my girlfriend, but i never ejaculate when she's giving me oral, or simply masturbating me. It is normal ?
Try anal. If you still can't unload, you don't have the first prerequisite of the sexual response cycle--attraction. Is she butt-ugly or 100 lbs. overweight?
What sort of porn do you look at when you masturbate. That tells you a lot about what sort of sex you need in order to cum and to orgasm (which can be two separate things for some men). When I first got married my husband rarely cummed and never orgasmed when we had sex. I looked at all his porn and talked to him about it I found out what he needed. He's been cumming gangbusters and having huge orgasms (just about) ever since.
No. In fact, if you don't ejaculate from that sort of stimulation, you are at risk of developing a rare and potentially damaging condition called Basic Ultra Local Lack Semen Hosing Into Therapeutic Touch (BULLSHIT for short). It can be remedied, but I'll need 8-10 uninterrupted hours with your girlfriend, teaching her proper techniques to apply. My fees are modest.
To be honest, in my adult life (not counting adolescence, when orgasm would happen at the slightest touch), I've never climaxed from Oral alone - and only once from Mutual Masturbation. I find it is possible, but can take a great deal of patience & persistence from the partner.