Interfaith marriages can work, but the likelihood of that happening if one of the partners (particularly the male) is a JW is a whole different ball game. I had a friend with a JW mom and a nonbelieving (i.e., not a church goer, not religious at all) dad. Because her dad was "head of the household" and had the say-so, she got to go to her cousins' birthday parties and have some normal childhool experiences. She was lucky.
That having been said, I believe it is less about religion than it is about the two people and their maturity and readiness for marriage. As Dr. Laura says, love is a good start, but nothing more. She points out that once a child is born, the religion moves to the forefront. If one partner is Catholic and want to have the child christened, and the other partner is Pentecostal, then there will be problems.
Sit down with your sweetheart and work out what the rules are going to be. Get pre-marital counseling. Understand yourself, and understand your partner.
Best wishes,
SandraC