My Husband Had A Vasectomy Reversal June 2011. We Got

My husband had a vasectomy reversal June 2011. We got preg and have one son who just turned 2. We have been trying now for over a year, and have been having sex every other day the week before, week of and week after ovulation. Many times, he gets hard, but then limps out right in the middle. It devestating him. I told him that if God wants us to conceive we will, but he is convinced his penis isn't working. I thought maybe there is scar tissue? Is that possible??