Tenants in common gives you more protections and you can specify in a deed of trust what you would want to happen in the event of relationship breakdown (eg if one of you has first dibs to buy the other out, or a time limit on doing so etc) which is definitely better to decide now whilst you still like each other!
Further tenancy in common allows parties to hold unequal shares of property interest. Joint tenancy requires each co-owner to hold equal shares of property. Further, co-owners must transfer the deed at the same time. In this sense, joint tenancy is rigid compared to tenancy in common.
Unlike joint tenancy, where each owner has an equal share, tenancy in common allows for specific parts or percentages of the property to be owned by each tenant. This type of ownership is often seen in situations where family members or business partners want to maintain separate shares.
Further research proved that it is not illegal to live together as boyfriend and girlfriend in Utah. The only states that legally penalize cohabitation are Mississippi, Virginia, Florida and Michigan.
Perhaps the most common way for unmarried couples to take title to real property is as "tenants in common." Unlike a joint tenancy, a tenant in common has no automatic right to inherit the property when the other partner dies.
Joint tenancy is most common among married couples because it helps property owners avoid probate. Without joint tenancy, a spouse would have to wait for their partner's Last Will to go through a legal review process—which can take months or even years.
By jointly owning property, you may find yourself party to a lawsuit if your co-owner is sued or the asset could be lost to a creditor of your co-owner. If your co-owner becomes incapacitated, you could find yourself “owning” the property with the co-owner's guardian or the courts.