So use it. Why would God be so petty as to call a contraceptive evil? Condoms prevent STDs because they are transmitted through fluids.
Sex is not a connection or whatever to the lord, nor is it purely for pro-creation. Sex is a need in the relationship. If you avoid masturbation and avoid having sex due to fear of pregnancy and are afraid to use contraceptives, then the need will find a way.
This is where cheating comes in. If the sexual need is not fulfilled, then you instinctively will have doubts (this is all assuming emotional needs are being met, and lets not forget financial).
Since you are religious, why would God force you to only have sex with your spouse for pro creation? Why would God call it evil to use contraceptives, but not evil for you to take medicine to cure an illness? They are technically the same.
Consider the financial troubles if you have another kid. Consider the emotional troubles if you do not have sex, consider why it would be possible for divorce in the first place if marriage is sacred, especially when divorce is so common these days.
Think about it, and do what
you think is best for you and your wife. If you don’t think Condom usage should be sinful, then God shouldn’t hold it against you for using your brain, the organ he apparently gave you.
EDIT: ** Besides, isn’t God all forgiving? So why would he be mad if you do something that will save your sacred marriage? Would a forgiving God punish you for something so minor?**