I am 25 years old and have been with my wife for 8 years (3 married). We used to have sex all the time, after we had our 2nd child, it seems that her sex drive went down. We stopped have sex regularly. We tried having sex the other night and I couldn't get hard for a while. When I finally did, it only stayed hard for about 5 minutes. Then we stopped because I couldn't get it back up, even after she tried oral sex. Please help, any advice?