This is not necessarily so. Gambling can be fun if you don't risk amounts which you can't afford to lose. Gambling can even help in making a relationship last, when both partners are engaged in the process. But you are right in the situation when only one partner is a gambler, then indeed one have to choose either gambling or the relationship. Gambling consumes too much time and if you are not with your partner in it together the relationship will end sooner or later.