Don: No.
Not until you clearly define the purpose of this separation with your spouse. There are no rules except the ones you make or don't make. Dating is one of the first issues to be addressed when starting the conversation with separation. Here is why:
Marital separation can have many different purposes.
1. It can be a cooling-off period. You and your spouse have wisely called, “I give up.” Now, you need counseling to address the underlying conflicts that have brought your relationship to the brink. It doesn't mean you will stay married and reunite in one home, but it will be a time to see what is possible before taking the next step. It can be a time to slow down and find CLARITY about your needs now. Don’t make it an emergency when it is already very unsettling for both people. SLOW DOWN.
2. It can be a way of warming up to the reality of divorce. Some couples have things that are not repairable, and separation is just a step for the children and for each person to face the end of a marriage and an intact family.
3. It can be a time to step back, work on the relationship issues, and connect and rebuild the friendship that has been lost.
Whatever the reason for a separation, it is best to get the dating option out on the table and decide. If you don't make a conscious choice, you create a potentially volatile situation if one spouse thinks one way and the other thinks another. The rumor network is very active now, and Social Media can add to the complexity of your situation. If left vague, your children could end up in the middle when you or your spouse is spotted in public being affectionate with another person or hearing from a best friend what they heard from their parents.
So, if you want a cocoon to work on your marriage and to see if a future is possible, then DO NOT DATE. Talk with your spouse up front. If you or your spouse wants to date, then it is doubtful you will be able to focus on the trouble in your relationship and repair it successfully. As long as either of you dates or has a romantic friend, neither will be honest about the issues that need to be faced between you. You will share more with your date or romantic friend than your spouse. You will compare your spouse--- shows your worst side--- with someone trying to impress you. Don't mix apples and oranges. Get clear about what you want. What you do in this area has a tremendous impact, constructively or destructively.
If either of you want to date, agree that dating is okay. Agree to keep it far from the children and not in each other's faces. Your separation is a time to take thoughtful steps forward, but know that this makes divorce more inevitable. See the separation, in this case, as a transition to divorce. Work on getting along for the children's sake, not to rekindle a possible relationship. Start thinking about child custody, visitation schedules, and creating a parenting partnership for your children, not remaking a marriage. That will soon be over. This is a pathway to deal with the business of change and divorce.
When a couple is on the brink, there is so much emotional pain. It is natural to want a new and fresh, soft place to land, talk, and be physically close to what a new dating relationship would provide. Many people don't realize the consequences of dating during separation until it is too late. Crossing this line is hard to recover from. If done secretively, the breach of trust and hurt that results is hard to undo, no matter what was assumed.
So, don't assume; discuss. Decide sooner than later. It is common for those on the brink to reach out to an old high school or college girlfriend or boyfriend who wants to revisit old times and maybe create some new ones. Don't go if you want your marriage to last. Know that you are not at your best right now. You are wounded. No matter who you meet, a big part of yourself and attention is devoted to your painful marriage and family situation. It is natural to want an escape. Find a way to step back instead of stepping over this line.
If you must date, keep it very light; it will be difficult, if not impossible, to be emotionally open until at least a year after the divorce is final. A part of your brain and nervous system is engaged with divorce until it is legal. Give you and your children a chance to adjust, heal, and recover from this unexpected turn that life has brought.
But if you want to try and work things out with your spouse, bring your best self to the most complex issue you and your spouse are having. If you don't want this marriage, get your best self to end it with clarity and respect with a parenting partnership in the future.