If you have come to believe that the Catholic Church is the one, true Church, then you have an obligation to become Catholic. If you become Catholic, you cannot receive an invalid communion at non-Catholic churches. As for your spouse, a spouse does not have the right to deny you the ability to follow your conscience.
Under certain circumstances, a conversion to Catholicism does not have to be made public. But do you really think you can hide for long that you have become Catholic from your spouse, especially since you will have an obligation to go to Mass on a weekly basis? How much more will it upset your spouse to find out that you converted secretly, without informing him (or her, as the case may be)?
If you want to become Catholic and receive the sacraments, I can only recommend informing (not asking) your spouse, assuring this person that your conversion does not mean that he or she must convert, and acknowledging that any children you have who are below the age of reason cannot enter the Church without the spouse’s permission. (Once the children are old enough to request conversion on their own is another matter, but hopefully one you will not have to deal with at this time.)
You are in our prayers. God bless.
