I'm in a bad relationship, of which there is no intimacy. We do have sex, but it is entirely focused on him. I give him oral, kiss, but he doesn't really touch me apart from penetration. He finishes in maybe 2 minutes and then rolls over to sleep or goes about his day.
I try to talk to him about it, I tried 'his/her nights'. He is just not interested in sexually satisfying me.

Iv started to fantasize about being with other men.. I fantasize about meeting men at work, while I'm out etc.. I can't help it. I'm SO sexually frustrated, I feel constantly aroused. I masturbate frequently and it doesn't even take away any of the urges.
I do not condone cheating, but I feel if this is to go on for many years I may end up doing something I regret horribly.

Iv tried to leave, or ask him to leave and he won't accept a breakup, we have young children together so that's the main reason I feel like I'm stuck in this situation.

Any advice to spice up our sex life? To bring up my frustrations without attacking him or making him feel Bad? I so badly want a connection with somebody, its starting to hurt.