I agree with pensmama in that if it is clear that a lubricant serves as a spermicide, it isn’t wrong. I don’t agree with the principle of double effect being a reason why it could be used if it did contain a known spermicide, as people often forget that one of the criteria for the principal of double effect to be (and I took this from the link above)
In other words, you can’t assume that just because your intentions are good, you can allow bad results to happen… you have to evaluate whether the good justifies the bad. Let’s say condoms made sex more comfortable for you, and you were not using them to avoid pregnancy, but for comfort… You wouldn’t be able to justify the use of condoms even if the reason for using them was not contraception.
But going back to your question, I would use lubricants that are not advertised as having spermicide/being contraceptive. Research it a little, and you may find that there are mainstream ones that aren’t really contraceptive.