I'd say just find one good woman and stick to her. People aren't televisions or some household appliance you can change whenever you want to. I don't believe that there's someone predestined for us. But I do believe that through patience, understanding and effort. We can cultivate a relationship that could last a lifetime.
We're 7 billion people on the planet. It's unrealistic to think there's only 1 person that is a "soulmate" especially when you know only about 0.000001% of the world's population. There might be a person on the other side of the world that would have been a perfect match for you but whom you'll never meet.
There are many persons that can be very compatible to you and could be a potential significant other, though statictically they represent a small percentage of the persons you know in general. However, life is all about choices. You meet one of those persons. You fall in love. It starts with a passion but with time the passion reduces, it doesn't mean the love is dead though. You have the choice to stay loyal to that one person you love, or break up or cheat etc. In my opinion that is the whole core concept of marriage, and as well as people who cheat or decide to divorce.
Sometimes the match was truly not compatible and in that case it wasn't really love, but I think the reason why many people cheat is because as soon as they meet another person that was on that list of potential significant others, they think their current love partner is not "the soulmate".
That is why, I don't believe in soulmates. Just choices of staying with a partner you fall in love with.
No, there can be multiple! You don't have to love only one person for the rest of your life, it can come in different times. Just because you love is more for another person doesn't make your past love invalid.
It would be nice to know that somewhere on Earth is someone only for you. That one day you will meet each other. It is a nice dream but still dream. However, sometimes I let myself to think about it - that's my romantic side. Down to earth side of me thinks that - world is not that perfect place, where there is only one person for everyone. We have choice and it is good. So I believe that Guy/girl dreamy exists only in our fantasies and helps us to find that one in real life.
I personally believe in soulmates. I do however think that most people never meet there's and you can fall in love with lots of different people and not even realize your missing out on something unless you had it and lost it :/.