Is it selfish to leave a relationship for your own happiness?

No. Staying in a relationship that's wrong for you teaches your children unhealthy patterns, prevents both partners from finding fulfilling connections, and often leads to resentment. Self-care and healthy boundaries are not selfish.

What if I'm leaving because of timing, not incompatibility?

Timing issues are temporary; incompatibility is structural. If you're aligned on values and vision but struggling with circumstances, couples therapy or a defined period of change can help. If the fundamental mismatch remains, timing won't fix it.

How do I make this decision without regret?

Separate your decision from your emotions by writing pros/cons, consulting a therapist, and testing outcomes mentally: "If I leave, in 5 years will I feel relieved or regretful?" Your gut answer reveals your true preference.