While I did have an interest in horoscope compatibility, and did contemplate it, I didn't use numerology at all. I understand that for some cultures it is compulsory for a numerology reading, but it wasn't for mine. In fact, it is sort of discredited as bogus. The reason why I didn't take it was because I felt that I truly loved my then-fiancé, and if two people are dedicated to each other and understand each other well, then there is no reason to forgo a relationship just because of an incompatibility in the horoscope.
No you should not rely on numerology solely, as it is not an entirely accurate measure of how happy or successful your marriage will be. There are many factors that make a marriage, and people's personalities do change over the years, which can change the dynamics of the marriage, Numerology may be a fun aspect of marriage compatibility, but is not the authority on how your marriage will work out.
Some people believe in numerology compatibility, but it is still not a guarantee of a happy or long-lasting marriage. We are all individuals and some are more compatible than others. I would rather concentrate on getting to know the person really well. Listen to your gut-feeling instead of convincing yourself that you seem compatible. You might sense more than you realise. If you feel uneasy though you are unsure why, it is a good idea to listen to it anyway.
You definitely should not rely on any one thing in particular to plan your wedding, other than something you both believe in as higher than yourselves. You can use numerology or other methods to decide different aspects of your wedding, but only if you believe it truly resonates and feels right to both you and your spouse. Make sure the directions you are given match up with your values and beliefs in your life and within the context of your relationship as well. Your wedding is a one-time deal so just make sure it is in line with what your true hearts dreams and desires are for your marriage.