1. Plan several sessions of “hard” talking with your potential spouse. It is essential that you temporarily forget the romantic elements of your relationship (I know this is next to impossible) to talk business. Blending families is one of life’s most difficult challenges, which is further compounded when both parties have children.
2. Don’t try to be the stepparent before you legally occupy the role. Prematurely playing a role will create problems once you legitimately occupy it. It is essential you do not assume roles you don’t occupy. If a child (or future spouse) treats you as a parent, it doesn’t mean you are one. Troubles brew when people push themselves, or are pushed by others, into roles they do not occupy. (This is true even beyond families!)
3. Bridges are best built before they are needed. It is essential that you insist on multiple meetings with both parents of ALL the children before you consider marriage (yes, you did indeed read what you just read). These meetings will focus on methods of co-parenting in order to secure everyone’s best advantage. If implementing such meetings seems overwhelming to you, you are probably heading for a minefield of countless unexpected, unwelcome complications – that will seem (believe it or not) even too large for love to overcome! What is avoided (denied, glossed over, minimized) pre-wedding will rise like a rabid monster quite soon (a month, a year, or even ten years!) after the wedding.
4. Financial integrity is as important as sexual fidelity! It is essential that you look into every detail of all financial records of your spouse-to-be and offer your own finances for similar scrutiny — before you plan a wedding. Persons who cannot responsibly handle money are unlikely to be able to handle the pressures of thriving within a blended family. If a would-be spouse suggests information of his or her finances are off-limits to you, wipe the dust off your feet and depart, no matter how much love you may feel. Authentic love, apart from having many other facets, is also measured in the degree of financial partnering established between lovers. Resilient love seeks the wise, open use of combined resources. Because blending families also often involves complex financial arrangements (child support and so forth, divorce costs, education bills for children of a former marriage) hiding the details from a would-be spouse is exceedingly unfair to all involved. I DID NOT say you have to SHARE all the money — I said you have to KNOW about it and plan about it.
5. Flee blamers. An adult who blames his/her former spouse (or parents, or childhood, the new political order) for everything will also, before long, blame you for everything.
6. Avoid people who cannot engage in civil conversations with an ex, with their parents, or their children.
7. Getting Johnny (or Mary) a stepparent will not ease his dissatisfaction with the divorce, school, or his craving for a “real family.” It is essential to understand that getting married will not solve any but the most superficial current family issues. Blending families is likely to unveil and exacerbate more problems than it solves.

All this said, and so much of it sounds negative, blended families hold the potential to enrich and empower all the people involved. Some of the healthiest, happiest families I have met in many years of meeting with families (in all manner of circumstances) have been blended families! Go for it, work through all 7 points above, and you will be all set to go!